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Dec 02, 2013, 03:07 PM
Altitude is my friend...
Depronicus's Avatar
Quote:
Originally Posted by CaribbeanBlue
Is it UV stable? ie does it rot with sunlight?
I have many old foamies that have spent a lot of time in the sun, and I haven't noticed any deterioration of the tape at all.
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Dec 02, 2013, 10:55 PM
Registered User
davereap's Avatar
Ive been using tape for a long while, a lot of my foamies are fully Tape covered for stiffness and décor..
however the packing strapping does as a CF spar replacement.. that's the point , me being a tight old modeller, CF is now an unneeded expense..
Dec 03, 2013, 02:00 AM
Altitude is my friend...
Depronicus's Avatar
Quote:
Originally Posted by davereap
...however the packing strapping does act as a CF spar replacement.. that's the point , me being a tight old modeller, CF is now an unneeded expense...
Okay, now I get it. CF from a local hobby shop can be staggeringly pricey, for sure.

That's why I often include a few pieces of it in HK orders, even though I may not actually need it at the time. Their carbon fiber tubing and rod prices are so low I get some just to have it in inventory. I know I'll need it eventually.
Dec 03, 2013, 03:43 AM
Marty Petri Sr.
mbpetri's Avatar
OK guys, this is called a discussion forum, which means there has to be room for an alternate view.

I used the Strapping on my Super Decathelon. Specifically I used it on top and bottom of the foam spar. Yes, it worked great and I swore I would never use carbon rod again.

One day, I was at the local Hardware Shop and I found the Fiber Glass Mesh Tape used for drywall applications in lieu of the traditional paper tape for mudding seams.
Now I swear I'll never use Strapping Material again.

This stuff is as thin as a sheet of printer paper, won't stretch or tear. Weighs a lot less than the strapping material.

For Someone reading this forum that does't understand the principle at work, I offer a brief description.

The Fiber Mesh Tape and Box Strapping have the same unique property, It wont stretch. You could tow a car with it, it's strong. But both have no stiffness by itself, it has to be part of a sandwich, the thicker the better. The tape or strap on the bottom keeps the spar or wing from bending upwards, the top tape or strap prevents bending in he downward direction. So why does it still flex you ask? because the foam is actually compressing making one of the straps ineffective (loose if you will) Shear webbing would fix the spar, nor sure how to fix the wing. The denser the foam, the less compression. The thicker the foam, the compression is distributed by more foam area.

Dave, I know we both hate to spend money, the Strapping Tape can be had for free as mentioned in an earlier post, but the fiber mesh tape is about 50 cents US money for a 1" wide roll. You can strip it with a hoppy knife for smaller widths, it doesn't fray or unravel. Some brands have an adhesive backing, the stuff here in Thailand does not. Make sure you ask for "Very Thin"

My Foamie Hog Bipe uses the mesh tape.

Marty
Dec 03, 2013, 12:07 PM
Registered User
I have a 6" wide of fiber material stuff for sealing roof. it's pretty thin. $5 for a 50 foot roll.
Acts pretty much just like fiber glass as far as Im concern.
Cut it to whatever I want. Use epoxy and thin it out with alcohol..ect.
It'll last me a life time. The strapping tape is going ease my pains.lmao

Depending on the type of wing I build.
I can get 24" 3mm fiberglass rods at the 99 cent store. But it's round.
I personally don't like cutting into the wing, if I don't have too.
The strapping tape is flat and will create less parasite drag.

Well, im rather lazy...one strapping tape and one piece of DTF as a spar
stack vertical would do the same trick as laminating 3 dtf pieces together.
Just sholve it between the wing sheet.
Easing more building pains.lmao

It's going to be plenty strong for a park flier.
Come on now. Im not going fly it 100mph at a local park.
I don't need to over build if I don't have to.
Plus it's dirt cheap..I'll do more evasive aerobatic closer to the ground
and not worry about it crashing. Quality stick time....
Dec 04, 2013, 04:14 AM
Registered User
davereap's Avatar
fibreglass rods are cheap...but they are heavy in comparison to CF and strapping.. but on bigger models will be fine...

If you are going to cut the wing vertically why not use a balsa strip placed vertical for compression resistance and the straps top and bottom of the balsa... a real I beam....

again how thick is your wing, because if its more than 6mm just the strapping will be enough..
I use a lot of depron 3 x 6mm layers is stiff enough with no reinforcing spars on short wings, but more than 36" and the flex starts to creep in ... EPP is worse, Ive got a 24" mini V wing that has 3 layers and it flexes like mad.. that flies fine.. and bounces well, but the strapping will definitely help if and when I can be bothered.. I will have to remove the Velcro and box over the gear in order to position the straps..
Dec 04, 2013, 04:22 AM
Registered User
davereap's Avatar
In the previous picture the glider seen has 4mm CF box spars in a multi layer depron wing.. the wings are about 12mm thick so perhaps strapping would have worked instead..
certainly it would have reduced the cost by more than half.. the depron is rarely more than £5 for a couple of sheets... the CF was £9 for two lengths

I am all for doing my flying as cheaply as possible, foam is a godsend and any bright ideas are worth a go..

take the 12mm strap, make a cut at the centre of an end, and the length can be torn down the middle.. this gives a nice 6mm strip..
So I used it to reinforce a leading edge on my latest model... what is good is that it can be bent/creased to follow bends or angles
The leading edge reinforcement weighs 2gm with glue... a 1.5mm CF rod 1M weighs 2.6gms no glue..

EDIT ... the model below has been flown , and is a real treat to fly...it is a small leadfeather Yak55....
https://www.rcgroups.com/forums/show...64237&page=809
its had a few good bumps, me going too mad and mid air collisions, the strapping is doing its job well there has been no damage, apart from a broken prop...
Last edited by davereap; Dec 08, 2013 at 07:48 AM.
Dec 07, 2013, 10:16 AM
Registered User
davereap's Avatar
another model is on the go using pallet strapping on the wing
Last edited by davereap; Dec 08, 2013 at 07:43 AM.
Dec 07, 2013, 11:48 AM
Registered User
ozmo01's Avatar
Vertical installation as mentioned by Proppyjon could by installed in an arc for bi directional stiffening. Especially helpful in stiffening up a mid motor plane such as a Firefly delta.
Sand ( course works better) the strips and clean with solvent no matter where you use 'em.
This stuff has been used in Foam combat "smack wing" construction for a long time.
It has been called "Poor Man's Carbon". In a smack wing it is placed vertically, sandwiched between the EPP LE foam and the blue foam that is the wing materiel from the spar back.
It comes in a WIDE variety of widths and weights some with fiber stranding even.

Your Sticky type glues such as Goop, Welder that stay flexible work well. TEST FIRST OF COURSE!
Dec 12, 2013, 02:00 AM
Registered User
davereap's Avatar
On my Yak model I also used the strapping down the fuzz centre line, putting it either side of the horizontal sections nose to tail..
Then put the verticals on top of the strapping, butt joined ..
Afterwards I did think I could have used some split strapping along all the edges instead..
Or as well....
Dec 12, 2013, 05:20 AM
Ldm
Ldm
Ldm
Ldm's Avatar
Interesting thread but some misconceptions
1)carbon fiber rods are expensive because they add rigidity even if misglued and 1 or 2" interval gaps. Tape of any kind is weak if its total strength from left to right is compromised by any gap in its adhesion.
2)tape of any kind can pull a wing up , down , left , right depending on how it was applied, carbon rods will not do this unless its intended and built that way
3)fiberglass tape is not new as a model tool and in fact used in the early glow engines trainer plane (Duro-fly) for the wing strength but only applied to the bottom of the wing to carry the load and reduce wing flex upward.
4)Yes carbon fiber is expensive but there is a reason why military, Nasa and so many other high tech flight application use it, its simply unmatched in "super materials"
Dec 12, 2013, 08:26 AM
Registered User
What is the best glue when using this strapping?
Dec 12, 2013, 02:24 PM
AMA 353531
rdeis's Avatar
Quote:
Originally Posted by davereap
...If you are going to cut the wing vertically why not use a balsa strip placed vertical for compression resistance and the straps top and bottom of the balsa... a real I beam....

again how thick is your wing, because if its more than 6mm just the strapping will be enough..
My foamystang https://www.rcgroups.com/forums/show...ht=foami+stang used strapping on the fuse and it worked great. The wing is a 48" span hot-wired clark-y and it needed a wood spar cap on the top. (tape-only spar allowed it to fold and spin in during a high speed spiral dive test. The fuse survived.)

Super materials unquestionably perform better, but the extra performance is often unnecessary, and *very* often not worth the added cost.

For depron, any good contact cement ought to do.

I used epoxy to bond the straps to the fuse, it's made from 2" thick white insulation sheet.
Dec 14, 2013, 01:18 AM
Registered User
davereap's Avatar
best glue is a contact adhesive suitable for the foam you are using.. I do a lot of depron building and uhu por is ok for depron... on EPP other general contact glues can be used because EPP is not disolved by the solvents in the other glues...

re.. misconceptions... I am talking strapping here, not talking fibreglass reinforced tape.. or plastic tapes.. all tapes are a lot more flexible because even when they don't stretch they will compress, the strapping stuff doesn't stretch, and doesn't compress , but it will bend or flex...it can be bent at right angles as seen in my pictures...
For my smaller foamies it is more than strong enough... EPP without the CF or strapping is very floppy.. and with it the wing is more than stiff enough...
I used to be using 3x0.5mm CF flats as wing reinforcement.. now the strapping will do the same job with ease...
so I replace two lengths of flat CF with 2 or 4 strips of strapping.. that's £6.50 for the CF or £0.18 for the strapping.. its not a difficult choice there for me....lol...

where the strapping might loose to CF is when the wing gets well overstressed.. talking big forces here... big models perhaps.. the foam between the layers eventually will be compressed enough to let the strapping fold inwards as the wing folds upwards.. or the strapping might come unglued on the top surface allowing the wing to fold upwards...
No different to a foam veneered wing.. except a foam veneer is over the whole wing area so gives a stronger overall finish..
with straps the forces are concentrated on a smaller area, so it is possible to compress the foam between the straps easier..

The sort of models I fly are the sub 30oz size... much smaller usually , so in general stresses are comparatively low.. the little EPP ones are flying at 4oz .. CF or strapping on those is not even essential... however the wings get well floppy without some stiffening and the ailerons don't work if the wing flexes too much...
Last edited by davereap; Dec 14, 2013 at 01:36 AM.
Dec 14, 2013, 05:09 AM
Marty Petri Sr.
mbpetri's Avatar
Dave,

I wish you would give the fiberglas tape a try before being judgmental. The tape doesn't compress, the foam beneath it compresses. It's lighter than your strapping, cost is about the same, and I bet the strength is as good or better, I did tow my car with a single 25' length, it never broke or stretched.

Marty.


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