Pyramid tent design

By: Tim

On: November 23, 2021

The new polyester tent pitched in readiness for its first alpine flogging.

Pyramid tent design model

A pyramid tent spreadsheet design model for a square (4 sided) backpacking pyramid tent with or without bell walls for terrestrial or snow camping.

Background to the pyramid tent design

Basics

For years I have been a fan of DIY pyramid tents (or more correctly bell tents or pyramids with short optional walls.

My first silnylon pyramid tent was ambitiously designed with twelve sides. "A beautiful looking design, I thought, but fiddly to set up and it had a large inefficient footprint that was not matched to the shape of multiple sleeping mats — My first silnylon pyramid tent was ambitiously designed with twelve sides. “A beautiful looking design, I thought, but fiddly to set up and it had a large inefficient footprint that was not matched to the shape of multiple sleeping mats.

A square pyramid tent designed with a small orthogonal footprint that is easy to set up. It is optimised for maximum sleeping positions. It also provides spaces for each occupants pack storage and for a small central tent heating wood stove when required for backcountry snow skiing trips.

I have liked these tents for a long list of reasons:

Simplicity.
Low cost,
Wind stability, including low and high pitching versatility,
Low backpacked grams/person for multiple comfortable sleeping positions,
Versatility when snow camping with a tent stove, and
Walk-in or stoop-in access and head clearance for comfort for both snow and terrestrial camping.

I also like single skin floorless designs that easily accommodate multiple people, tent stoves and allow snow excavation for winter ski based camping to provide standing and sitting comfort after long days of fun skiing. I also make the tent canopy so that it can open up fully (like a cape) so that it can dry quickly, or can be closed up to be used as a bothy shelter in an emergency.

Pyramid tent fabric

Silnylon. I have used silnylon for most of my pyramid tents. This wonderful innovative fabric has revolutionised DIY tent making. However, from my experience, it has several significant drawbacks for pyramid tents:

Wet stretching of the many long unsupported tent panels,
Frequent adjustment of guyline tension,
Dreaded cold night condensation on the inside of the tent,
Tent ‘rain’ or ‘snow’ when strong winds shake the the slack tent, and
Slow drying or carrying a heavy and wet tent when cold early morning packing is invariable required when using a winter tent.

Polyester. Recently, I have successfully experimented with a breathing polyester tent design. This breathing tent made from cheap umbrella fabric is very rainproof and comfortable. It greatly reduces the condensation, speeds drying and eliminates the wet stretching issues that are associated with the silnylon fabric that I have used for many years.

Regarding an unwaterproofed fabric being rainproof, I can not explain this good performance as it runs contrary to some expert opinions and commercial trends. However, in practice, it gets ‘less wet’ and it also seems to dry-off water or flake-off ice very quickly on cold mornings. I expect this relates to the very hydrophobic nature of yet another wonder polymer for us backpacking tinkerers. “If those benefits are not enough, this umbrella fabric can be very cheap and can easily be made from discarded polyester and is infinitely recyclable (unlike nylon composites).”

Silver coated polyester. I practised making scale model tents from old umbrellas and discarded tents and was impressed with the warm skin feel of the silver-coated fabric. Surprisingly, the coating did not seem to make the surface feel any less soft.

When preparing to purchase my first batch of polyester, ‘silver-coated one side’ was an option that was offered, so I went for broke and ordered it. I hoped that it might improve heat retention in winter and heat reflection in summer. I was certain that it would reflect UV radiation to give the fabric a long service life and prevent the fading of the beautiful flame orange colour that I observed with my first silnylon tent (as shown in the first photo above).

On the downside, the silver also blocks the radiation frequencies for radio reception. Overall, I feel that silver coating significantly improves the winter comfort of the tent and I have yet to experience a hot summer in it but am certain that it will be more comfortable and it has become my go-to tent fabric. “My smile in the photo below taken on the tent’s successful maiden winter trip may give you a clue about the polyester performance. It may just be I was relieved that it worked at all or it may have been that we had escaped Covids grip for a week to enjoy the alpine wonderland and some skiing at last.”

An experimental square pyramid or bell tent made from cheap unproofed polyester umbrella fabric. The tent provides great rainwater protection with less condensation, no wet stretching and is fast to dry on cold mornings. This post is about quickly determining the tent dimensions needed and how they may affect the functionality according to your backpacking camping requirements.

I thought this little ode might help to sum up my PE fabric preference ramble:

A heavier PE tent in my pack, how could it be fun?
Silnylon is lighter, but slow to dry without sun.
No stretching, less condensation, with PE at night,
Or barefoot, nocurnal excursions, to set the bitch right,
Packed dry on cold mornings, weight may be the same sum?

Bell wall and snow/bug skirts

I have always made my tents so that they can be sealed down to the ground or snow by having a bell wall and a snow/bug skirt. This makes the tent warmer and stops the entry of spindrift in winter and bugs in summer.

Traditionally, my pyramid tents have short bell walls (~30cm) that increase the clearance from the ground to make most of the footprint an effective sleeping place while keeping the footprint as small as possible. It also contributes to walk-in comfort and convenience. “The fabric used to make such a wall is marginally less than that would be used to continue the roof slope to the ground.”

Integrated bell wall and bug/snow skirt. More recently, I have made the skirt and wall an integral part of the triangular tent panel that I would have otherwise been attached by sewing. This saves the effort of cutting, seam allowances and sewing and makes the tent lighter and have a smoother finish with better drying properties.

It also means the formation of the tent wall seams is just a continuation of the pyramid canopy lay flat seams (see photo above). It also means that the stretch of each wall and skirt section is compatible with the associated tent panel above it. This equal stretching contributes to a better tent pitch.

A breathing polyester tent seam is prepared for sewing a lay-flat seam that connects the one-piece tent panels. The panel incorporate the main pyramid surface, the bell wall and the snow/bug skirt. Low profile spring clamps and plastic pads have been used to hold the lay flat seam glueing points together in preparation for the first row of stitches to make the sewing easy. For more details please see: Seam glueing instead of pinning.

Easier one-piece cutting. Cutting as one piece also means that particularly for a square tent, all panels are exactly the same shape and only require one* pattern piece to mark out the entire tent. The design model reflects this approach. “I think this feature forces good planning and leads to a more relaxed sewing project and to making fewer mistakes during the sewing as you and your sewing machine start to disappear in the growing tent canopy.”

*Note: While the pattern can be one piece, it must be used from the correct side to make correctly matching panels if the fabric has a ‘front and ‘back’ finish that can not be interchanged. More on this later.

High and low pitching

Another survival feature of my tents is that I design them for comfortable high pitching with the bell wall or low pitching without the wall as a pure pyramid. This low mode is for survival camping in very strong winds when occasionally this can not be avoided. When pitched low, the surplus wall becomes a giant snow skirt. “Lastly, if conditions become so bad, the tent pole can be removed (if it has not already broken) and the tent can become a bothy bag shelter.”

This is the same orange tent as shown in the first photo above. The tent design allows it to be pitched low as a pure pyramid in preparation for a big overnight blow in open country. The tent walls have become enlarged snow skirts.

Pyramid tent panel grain orientation

The pattern and layout of the tent panels can at first seem complex, but the pattern for the square pyramid can be distilled down to a single piece pattern that can be used from an ‘A’ side or the reverse ‘B’ side.

I like to make this pattern from thin cardboard or similar with the ‘A’ and ‘B’ clearly showing. This helps me avoid stuff-ups during the project and the pattern can be marked with all critical markings to transfer onto each panel to make them consistent. I include the bell wall and skirt on the pattern if required. I stick them on as extra rectangles, as required. My patterns are for the bare panel size and I add the seam allowances at the time of marking out and hot cutting using a metal straight-edge.

Bias to straight grain tent panels. So far, most of my pyramid tents have been unconventionally cut out and sewn so that each radial seam combines a straight grain side and a bias cut side. This intentionally made all seams have a uniform and limited stretch. It is a tedious process that has worked as intended without the need for catenary seam curving. However, it does not let the bias grain stretch naturally and become taught as it otherwise would do. It leaves the adjacent bias grain fabric a little ‘baggy’. “Like the sails on an old square-rigged sailing ship. This effect can be seen, in the above photo of the silver polyester tent. (On the cross-grain fabric, to the right-hand side of the centre seam, and on the cross-grain fabric, adjacent to the right-hand side of the left ridge seam line.) Strong winds amplify this bagginess.

The following description and photos apply to this unconventional (bias to straight-grain) seaming method. Four of the panels can be cut moderately efficiently as shown below.

Square pyramid tent panel layout to have straight grain along the hypotenuse.

The other four panels can be cut very efficiently as shown below (The conventional cut).

Square pyramid tent panel layout to have straight grain along the long right angle side of the triangle. — Square pyramid tent panel layout to have straight grain along the long right-angle side of the triangle.

If the fabric has an inside and outside finish, then the pattern must be reversed ‘B’ to ‘A’ or ‘A’ to ‘B’ so that they can be joined with the correct face on the outside. “Always check with a little paper tent before taking the scissors to your precious fabric.”

Square pyramid tent panel layout to have straight grain joining bias grain along every tent seam. The straight grain of the blank triangle 'B' is parallel to the hypotenuse. The grain in the panels marked 'A' is in the direction of the printed lines. — Square pyramid tent panel layout to have straight grain joining bias grain along every tent seam. The straight grain of the blank triangle ‘B’ is parallel to the hypotenuse. The grain in the panels marked ‘A’ is in the direction of the printed lines. This ‘A’ then ‘B’ then ‘A’ again etc addition of panels is simple and the available edge for the addition of the next panel is always a straight grain that can be wrapped around the bias grain edge of the next panel to be added to make the first row of stitching of the lay-flat seam easy. This wrapping process is a little unconventional and can include silicone rubber glue tacking but it makes the sewing much easier for crap sewers’ like me ( shown in the fifth photo above, and described in my glueing instead of pinning post).

When sewing the tent together, I add each panel sequentially and this means that only a small area of fabric needs to pass under the bridge of the sewing machine. When doing so, I start with a straight grain edge and wrap the stretchy bias grain edge within the starting fold of the lay-flat seam. “It helps to manage the difficult stretchy edge by holding it in a ‘straight grain sandwich’ for the first line of stitches and after that, it is all easy.” I also have devised a silicone rubber glueing/tacking method that can help make the preparation of these lay flat seams between straight and bias fabric easier without numerous nasty pins and fabric creep. It works well for a crap sewer like me.”

Bias to bias and stright to straight grain tent panels

On the other hand, I have observed (somewhat late) that the conventional approach of, sewing pyramid tent panels, is to sew edges together bias-to-bias and straight-to-straight as in this hexagonal pyramid tent design. This may be the better approach as it should mean that the stretchy bias-grain seam can stretch naturally and the surrounding fabric can become taught by stretching in sympathy. They probably will need catenary curves for these seams to pitch well.

Luckily, the basic panel pattern remains the same and will have a simpler layout and a very efficient ‘cut’. However, there still is one remaining trick if the fabric has an inside and outside finish, as for my silver tent. The photo below shows what is essentially a rectangle that is cut in half along the diagonal leaving two basis-cut hypotenuse sides. These two triangles can not be put together correctly to form a tent face (unless one is flipped).

The pattern layout for half of the tent panels when all the joining seams combine a straight with straight and bias with bias grains side. The panels should be cut with the second longest side (drop length) aligned with the fabric grain. The remainder of the remainer of the pannels should be layed out the same way, but from the other side of the pattern. — The pattern layout for half of the tent panels when all the joining seams combine a straight with straight and bias with bias grains side. The panels should be cut with the second-longest side (drop length) aligned with the fabric grain. The remainder of the panels should be laid out the same way but from the other side of the pattern (B side) if the fabric has different inside and outside finishes (As for the silver tent).

Another rectangle needs to be cut on the other diagonal to make two correctly matching panels. Luckily this can be done easily by flipping the pattern to the ‘B’ side.

Square pyramid tent panel correctly matching for straight grain seams by one side being marked out with the pattern flipped to the 'B' side. — Square pyramid tent panel correctly matching for straight grain seams by one side being marked out with the pattern flipped to the ‘B’ side.

Why a square pyramid?

A square pyramid tent may be an inefficient design for one person because a sleeping mat length is rather wasted on the width of a tent for one. However, I seldom go adventuring alone. I like the fun and safety of the company of others and this leads to tent, stove, meal sharing and the list goes on. So pyramids come into their own by saving weight when travelling light on skis or walking boots with friends by sharing an already light tent (450g/person for two or 300g/person for three).

I have used another mathematical model to explore the features of an interesting hexagonal pyramid tent design. However, I was somewhat disappointed with the efficiency of the layout of sleeping positions and the very large footprint. I often need to squeeze my tent into sites between rocks, bushes and trees. I kept comparing it with my square bell wall pyramid tents. The square pyramid is versatile and almost 100% efficient for 2-3 sleeping mats and gear or alternatively two sleeping mats, gear and a small wood stick fired tent stove.

Sleeping mats and tired trekkers bodies fit optimally in rectangular portions of the tent footprint. Consequently, I have made my tents square so that they accommodate multiple sleeping mats across the ‘sleepable’ width of the tent that is opposite the entrance doorway.

This arrangement gives all occupants; fair access to their sleeping position and gear, a little wet mess room at the doorway and no excuse for walking on the gear of others. I also like to have a generous space for gear storage at the end of each sleeping position. This all makes a square design very efficient for multiple occupants.

In bad weather, a pyramid is fast to erect especially with two people putting a pair of pegs in at each corner. It makes an instant cover under which packs can be opened and gear organized. When packing up in rain or falling snow the process can be reversed, allowing all but the wet tent to be packed up undercover.

Lastly, if a little tent stove is to be deployed, it can be optimally located near the middle of the tent. In this case, it may use up one sleeping position if it is to be left conveniently assembled overnight for welcome rapid use the next morning to get a cold day off to a good start.

One pole is good and no pole is better?

An obvious benefit of a pyramid tent is that it only requires one pole. A further design feature of my tents is the simple loadbearing apex hem. This easily allows any bush pole to be used as the pole and because it can protrude through the hem that will close tightly around the pole, it does not need precision trimming to a particular length. Even better the tent can be suspended by the hem drawcord from a suitable overhanging branch to provide pole-less convenience and flexibility.

A bush pole can support a pyramid tent via the drawcord in a loadbearing apex hem. If the suspension cord is run over a fork in the branch above the tent apex, the tent canopy tension can be adjusted from inside the tent during wet weather when silnylon fabric stretches considerably.

A pyramid tent that is designed to be suspended from an overhanging snow gum, so that the snowpit can be excavated without the need to have a tent pole in the pit. A small tent stove is mounted up above the side of the snow pit.

Ultralight pole

When setting up the tent after a long day of trekking, having a lightweight pole ready for instant tent pinching is welcome, but it may not be storm worthy. Consequently, a very light pole can be used and simply splinted with a ski stock, walking pole or a bush stick.

A light and convenient tent pole that has been supplemented with a stick splint to make it storm worthy.

All this has led me to make a model that can help me explore square or rectangular pyramid tent designs to see what the optimum dimensions may be. They may be some help to others who like to make their own tents that are customised to share with others according to their unique camping requirements.

The pyramid tent design model

An image of the spreadsheet model is shown below. It has been filled with various tent dimensions that have been of interest to me. Unfortunately, it is not an active sheet that you can use to play with your design ideas. However, I would be happy to send an active copy to anyone who is interested (see details below). You also may be kind enough to let me know if I have made any mathematical mistakes that should be corrected.

Making more pyramid tent design models

The sheet shown below has multiple models (1-8) and the last couple can be revealed by scrolling to the right. They each have an editable colourless cell that can be used to provide a tent descriptor to save us from getting lost in all the possible design options.

I find that once I have run a test model it often causes me to ask many questions. Luckily, the model is very friendly to copy. Any unit of the model (within the outlined borders) can be simply copied into an adjacent empty column to make more models. This allows the creation of unlimited model outputs for side by side comparisons.

Navigating the pyramid tent design model

The orange cell is the place where I have added the conversion factor from Radian to Degrees (Check it by all means but don’t change it if it is not wrong!)

Input cells

The five numbered navy blue cells are for inputting various tent parameters. These have been set with my default values and feel free to change them, but you might like to keep some of my models with my default values showing for future reference.

Pyramid sleeping clearance. The minimum separation between ground and the tent canopy for a good nights sleep. My default value is 30cm. Digging in or excavating snow can also provide this clearance and much more.
Bell wall height. This should be set to zero if no wall is required. My default value is 30 cm which equals my chosen sleeping clearance. This means that most of the tent footprint is usable for sleeping with this wall height.
Snow skirt width. My default value is 10cm. Set it to zero if no skirt is required
Sleeping mat width. This allows the estimation of the number of sleeping positions that the tent width or length can accomodate. My default value is 66cm which is the width of my Exped down mat.
Tent fabric gsm. My tent fabric is rather heavy and my default value is 58 grams/square meter

The three yellow cells are for inputting the basic tent dimensions.

Note: I only use cm length units so that the subsequent calculation of fabric areas and weights will be correct. Also, for similar reasons, the fabric weight must be in grams/square meter (gsm). If you wish to use other units of length this will be fine and your outputs will be in the same units. “The area and weight estimates will just be rubbish.”

DIMENSION INPUTS

(A) Pyramid height. This is the vertical height of the bare pyramid from the ground (without bell walls).
(B) Long base length (LBL). This is the length of the longest side of the rectangular tent base.
(C) Short base width (SBW). This is the length of the ther base side and will be the same as (B) if the pyramid is square.

Output cells

The numerous mid-blue cells are the calculated outputs of the tent dimensions and other specifications. (Again, check the formula in these cells, copy them, but I suggest you don’t change them.)

Sorry, the list of outputs (A) to (Y) is a very long list of interrelated model outputs. “I nearly ran out of letters to index them.” They do model three different tent options at the one time (pure pyramid, bell pyramid and bell pyramid with snow/bug skirts). I find them all to be informative, and I hope you may too.

Output cell definitions

FUNCTIONALITY

(D) Pole height. This is the height of the tent pole of the pyramid and it will increase by the length of the bell wall if there is a length entered at line 2. Extra pole length will be needed when snow from the tent floor is excavated.
(E) Usable LBL for ‘sleeping length’. This is my estimate of the usable length of the floor space with a minum clearance as entered at line 1 for fitting the length of sleeping mats. Note: This computation only works correctly where Bell wall height (2.) does not exceed Pyramid sleeping clearance (1.).
(F) Usable LBL for ‘sleeping mat widths’. This is my estimate of the the number of sleeping mats that will fit side by side within this minum clearance length across the longest portion of the tent. The sleeping mat width is entered at line 4. Note: This computation only works correctly where Bell wall height (2.) does not exceed Pyramid sleeping clearance (1).
(G) Usable SBL for ‘sleeping length’. This will be the same as (E) if the tent is square or will be shoter if the tent is rectangular. Note: This computation only works correctly where Bell wall height (2.) does not exceed Pyramid sleeping clearance (1).
(H) Usable SBL for ‘sleeping mat widths’. This will be the same as (F) if the tent is square or will be less sleeping mats fitted if the tent is rectangular.
(I) LBL pyramid drop length. This the measurement down the face of the pyramid surface and would be used to make the pattern for the long orthogonal side of the two triangular panels that make up the long side of the pyramid.
(J) LBL drop+wall. This is the length of (I) plus the length of the bell wall entered at line 2.
(K) LBL drop+wall+skirt. This the length (J) plus the addition of the width of a snow/bug skirt entered at line 3.
(L) SBW pyramid drop length. This is as for (I) but is applicable for a rectangular design with a shorter side.
(M) SBW drop+wall. This is as for (J) but is applicable for a rectangular design with a shorter side.
(N) SBW drop+wall+skirt. This is as for (J) but is applicable for a rectangular design with a shorter side.
(O) Ridge. This the length of the hypotenuse of the the eight tent panel triangles that will be sewn together to form the four corner ridges.
(P) Pannel angle LB Rad. The angle of each the four ‘long base’ tent panel in Radian.
(Q) Pannel angle LB Deg. The angle of each the four ‘long base’ tent panel in Degrees.
(R) Pannel angle SB Rad. The angle of each the four ‘short base’ tent panel in Radian.
(S) Pannel angle SB Deg. The angle of each the four ‘short base’ tent panel in Degrees.

SPECIFICATIONS

(T) Pyramid fabric area (M^2). This is an estimate of the pyramid only tent fabric area without seam allowances.
(U) Fabric wt. (g). This is an estimate of the weight of the fabric in (T).
(V) Pyramid+wall area (M^2). This is an estimate of the pyramid+bell wall tent fabric area without seam allowances.
(W) Fabric wt. (g). This is an estimate of the weight of the fabric in (V).
(X) Pyramid+wall+skirt area (M^2). This is an estimate of the pyramid+bell wall+ snow/bug skirt tent fabric area without seam allowances.
(Y) Fabric wt. (g). This is an estimate of the weight of the fabric in (X).

Discussion and conclusion

From my playing with the model, it appears that a 230cm wide (give or take) square tent with a 30cm bell wall is about optimum for a two-person tent for terrestrial camping. It provides generous space for gear storage and a left-in place tent stove. It can be a three-person tent with minimal gear storage and no fixed tent stove. It also provides walk-in comfort (depending upon your height, Model 2).

Increasing the square slightly to 265cm and 10cm higher (Model 4) makes it a four-person tent with gear storage at the end of each sleeping position. It increases the canopy weight by only 42g/person. Alternatively, it would make a generous three-person tent with a stove. However, making the tent rectangular by shortening one side back to 230cm only saves about 33g per person, so this saving would not be worth the loss of generous gear storage space (Model 6).

I like to use the one tent for both deep snow and terrestrial camping, often on the same trip, so the bell wall is a very important comfort factor for me. However, if the tent is exclusively for deep snow camping with no need for the snow/terrestrial transition it could have a skirt and no bell wall and snow excavation could be used to provide the comfort factor. However, the model shows that this loss of versatility only reduces the tent weight by 160g. In Addendum 2, I consider how a single tent can be made to be a pure pyramid for optimises snow camping and a bell tent for terrestrial camping.

A very large increase in length or width is required before there can be enough space for two banks of side-by-side sleeping positions. Model 8 reaches this state, but I doubt that it would be comfortable living with so many in such a small tent.

While small pyramid tents have limited sleeping capacity, they can be used effectively as communal tents on ski trips. They can provide a warm respite from the cold world in seated comfort (BYO blue mat to sit on). “This is most enjoyable when the skiing is over and it is time for drinks and discussion of the highlights and the exaggeration of the exploits of the day.”

A square pyramid tent (~225cm square) sheltering skiers around a small stick burning tent stove. The tent is suspended by a cord from an overhanging snow gum branch and is connected to the loadbearing hem at the apex of the tent. Steps were cut in the snow leading down into the snow pit so that it provided comfortable walk-in seating for six or more skiers. The excavated snow was used to build a snow altar outside the tent to encourage the snow gods to send down some powder for the next days skiing.

A simpler square model

I realised that the model had grown a little complex by including rectangular tent designs as an option in the model. From my analysis, I concluded that the square tent was optimal and a model that only considered a tent with four sides of equal length could be much simpler and probably more useful. “So I ended up with two models and then a third.”

ACCESS TO THE SPREADSHEET MODELS

I could not find a way of embedding the working spreadsheet in this post. I would be happy to send the working spreadsheets by email to anyone who is interested in tinkering with it. Please use my contact form or use the comment section below for this purpose.

I have already found and corrected some little errors since posting so I would welcome feedback about the models and would like to know if you find any errors that need correction.

Tim

DIY breathing polyester tent for backpacking- Beat the dreaded condensation problem

Addendum 1

I made a 0.3 scaled test pyramid according to model 1 ~46cm high*74cm wide. I did this to test the stretching of the bias-cut seams (in polyester umbrella fabric) before committing to a full-scale tent with this seam design. I sewed it together with simple basting stitching on the bias seams, knowing that catenary curved seams would probably be eventually required. The pitch of the tent was not good and I could not get all the corner seam ridges taught.

A 0.3 scale model of my favourite pyramid tent top (model 1). It has been cut and sewn with bias cut corner ridge seams, rather than my favoured bias+straight grain seams. “I could not get the ridges to pull taught. As soon as I tensioned the seams in the middle of the pyramid, the corner seams became slacker.”

Next, I sewed crude catenary stitch lines along each corner seam. However, it did not greatly improve the pitch of the tent.

A 0.3 scale model of my favourite pyramid tent top (model 1). It has been cut with bias cut corner ridge and with crude catenary sewn seams, rather than my favoured bias+straight grain seams.

I was still disappointed with the pitch so, out of curiosity, I thought that I would remove one side panel from the pyramid and test its pitch as a hexagonal pyramid to see if this was any better.

A 0.3 scale model of my favourite pyramid tent top (model 1) that has been cut down to make a hexagonal pyramid to test the pitching. — A 0.3 scale model of my favourite pyramid tent top (model 1) has been cut down to make a hexagonal pyramid to test the pitching.

Again, I was disappointed with the lack of tautness of the corner seams however I tuned the pitching. It has given me a new insight into the possible value of my unusual (funny) bias+straight grain seams that I have traditionally used for my pyramid tents. “Maybe they are not perfect, but not so bad after all!”

Addendum 2

I had determined that an equal-sided square tent would optimally provide the maximum number of sleeping mat positions. I decided to explore a square tent design model that would equally allow the tent to be a pure pyramid optimized for snow camping where snow excavation can be done to use the entire footprint for effective sleeping positions. The same tent could be also be used for terrestrial camping with a smaller footprint where some of the pyramid fabric is used to form the bell wall.

In this model, I have simplified the input to a single value of the decimal fraction of the parent model. This fraction comes from the tent width (230cm) of my favourite parent tent divided into the desired width of the tent under consideration.

The table below shows the dimensions, weights and estimated sleeping mat capacity of progressively larger scaled tents with the dual function of pitching as a pure pyramid on deep snow (with a minimum 30cm snow excavation) or terrestrial pitching with a bell wall.

Bell tent configuration, terrestrial pitch Pyramid pitch over 30cm snow pit

Model# & description
	Tent width (cm)	Tent height (cm)	sleep mats #	Wt per person (g)	Tent width (cm)	Tent height (cm)	sleep mats #	Wt per person (g)	Wt total (g)

M2.0 Current favourite tent with fixed bell wall	230	183	3.35	241	NA	NA	NA	NA	724
M2.2 Current design with walls that convert to pure pyramid for snow pitching	230	177	3.35	248	266	177	4.03	186	745
M2.3 Large scale bell+pure pyramid tent	255	200	4.00	313	300	200	4.54	235	938

A comparison of scaled-up tents based upon my favourite bell tent. These scaled tents are designed to be pitched as pure pyramids for snow camping where snow excavation is possible. They also pitch with a bell wall for terrestrial camping where footprint space may be limiting.

The above model can also be used to determine the size of tent that can be made from a particular fabric width (eg 150 cm) or conversely what width will be required to make a tent of a particular size.

From my analysis, the design that is based on my current tent is the most efficient (186g/person). However, the larger tent, the extra space (not occupied by sleeping mats would be very welcome in a winter tent on ski trips. The weight of 235g per person is very small.

This simple model will also be available on request.

Addendum 3

Setting the footprint of a square tent as a true square is critical for optimum pitching, but is difficult to achieve by eyeballing in the bush environment. I contemplated the massive pairs of joined right-angle triangles of the tent panels during the design process and somewhat belatedly (~50 years late) realized that they could be used to set the tent base square the first time, every time. Here is a little post on the subject that may help others avoid the shame of a 50-year delay for this little discovery. Or, maybe the photo below will suffice.

Ultralight Backpacking Gear