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FT Simple Soarer - BUILD

#84
I fly DLGs, and I strongly doubt it would make sense; for one thing the quite immense stresses on the wing spar and especially the tail boom would tear the plane apart quite easily; In that respect the polydihedral and the 2-part fuse do not exactly help. You may be likely to be able to side-arm launch it gently to an altitude similar to what is possible with a javelin throw, but you'll definately have to add extra rubber bands to not tear the wing off.
Now, It is off course possible to add a load of carbon to strengthen it to perhaps be able to withstand a more powerful dlg launch, but in the end the planes basic aerodynamics gets in the way - it's just simply far too draggy to ever go anywhere high from a DLG launch, you need a plane capable of going fast, I.e. something with little drag and a rather thin airfoil.

For comparison The SS wing is about 3/4" thick with a chord of about 8" - that makes it an airfoil with about 9% thickness, which is not that bad, but it also has quite a bit of camber -especially the heavily undercambered wingtips(!!) and a nearly flat bottom on the rest of the wing, slowing it down quite a bit. A similar airfoil suitable for DLG would be something like the Mark Drela AG12-13-14 series (root to tip airfoils), which are about 5-6% thickness, semi symmetrical and has just a slight amount of camber. And it's regarded as fairly slow in DLG respect at that.

Don't get me wrong, there is nothing wrong with the the SS, It's just not constructed for DLG, but primarily for Hi-start, and likely great as such.

It may be quite possible to build a DLG from foamboard, but you'll need to get a bit closer to existing DLG's constructionwise to get something that'll be fun to fly as a DLG. Well, thats my opinion anyway.
If I were to point you in a direction, something like the Dream-flight Alula or other similar thin airfoil flying wing design would probably make a good starting point for a first DLG/SAL type plane, as the flying wing layout solves many of the strength issues quite nicely. In fact, the basic construction principle of a versa wing might very well be a good starting point. Maybe thin the wing down a bit by reducing spar height, maybe try to make it a bit semisymmetrical in shape (may also work nicely as it is...?) and remove the winglets and put on a central fin in stead, and you may be quite well under way already.

A single little word of warning though: On a HLG/SAL/DLG flying wing, CG will be a bit tricky to get just right. Just a bit too nose heavy, and the resulting increased up elevator will both slow it down quite a bit in level flight, making it more difficult to keep flying(it's closer to stall), and cause it to loop up over you at the high speeds caused by launch. A bit too tail heavy and it'll slam into the ground on launch. Keep it just slightly noseheavy and try to always launch it level to the ground, and build up the force gradually, trimming the CG back till it rises nicely from a level full power throw.


EDIT: The SS should do nicely as a HLG though, i.e. using a Javelin throw.......that certainly is what I'm hoping for myself......
This is the best info I've read thus far. I am on the fence about going to the SS as a first build/Fly or go the DLG way. Cost for beginner is the main thing for me right now. Thanks DKChris and you glider folks.
 
#85
50 yr old virgin! Am I on the right sight???

From the store page:

Wingspan - 57.5 inches (1460 mm)
Hi I'm Mark from Shropshire Uk
I have trouble putting a McD happy meal toy together!
Spent last few days stumbling round Internet
No Flying experience - No build experience
Total noob!!!!

Project: build a 2 meter (79 inch) wing span glider that will carry a Barbie
Why you ask?? To help son out with college project.
I got to this site via 1997-1998 Bradley J. Smith loverly helpful book, he talked about the charms of his first glider a"gentle lady" i searched for a foam version and found the S/S and was taken by the challenge and the enthusiasm and the clear instruction style.

My plan: build a scale SS thanks to DKChris for his very informative 120% build
Learn from this experience
Scale up to 2 Meter model

Question in the UK some of the material terms are different I know I can get 2mm foam (laminate floor insulation) has anyone built an SS with this? Any issues re hot glue?

Is it lazy and foolhardy to imagine I can slap plans on photocopier and pump it up to the 2m version that will be my second build???

Did I mention I'm trying to avoid hard maths???
Thanks for all your assistance and hope I have not posted in the wrong place!!!
 

ztoon

Gone with the Mistral
#86
Question in the UK some of the material terms are different I know I can get 2mm foam (laminate floor insulation) has anyone built an SS with this? Any issues re hot glue?

Is it lazy and foolhardy to imagine I can slap plans on photocopier and pump it up to the 2m version that will be my second build???
Hi Mark,
I made my Simple Soarer with 3mm depron, both wing and fuselage (first built without using 6mm depron or coroplast, didn't used any carbon spar either). I used tape to cover outside and inside. Tape cover gives rigidity, but I use it also inside to protect from hot glue. I've trouble with low temp glue (doesn't work very well) and high temp melt the naked depron. Longer process, but it works pretty well.
I made some scaled down FT planes (Viggen and Versa at 75%) with some modifications. A 2 meter SS may require some spars in the wings and the use of 6mm depron instead of 3mm (if depron is used) for the fuselage, but yes I think it is "do-able" without so much problems.
Can't you shrink the Barbie down? :D The original 1.5m SS flies well !
 
#88
Hey!

Sweden is only offering bad weather, so in a moment of weakness I decided to build my 70% FT SS. But I made the wing longer, 143cm.
20150110_092916.jpg
20150110_092933.jpg

I hope to maiden it as soon as it is dry or at least not wet snow. :)
/dews
 
#89
Orient spar vertically?

I've searched this thread, and the forum in general, for an answer to this, to no avail, so I'll ask it here and hope that I didn't just miss it elsewhere.

I've not worked with foam board before, and I'm considering the SS as my entry into the material. My question is about the foam pieces for the foam wing spar; it looks to me from the build video that the spar strips simply lay flat between the top and bottom of the wing. The build video clearly explains that the main purpose of the spar is to help shape the wing, and that it is not primarily for strength. But wouldn't it also supply significant strength if the spar were positioned on edge (paper on the foam running vertically rather than horizontally)? Obviously, the dimensions would have to be adjusted to maintain the correct separation between the top and bottom wing surfaces, but am I missing something here; maybe it doesn't matter; maybe on edge isn't notably stronger? (Maybe I'm seeing it wrong in the video?)

Just wondering.
 

Craftydan

Hostage Taker of Quads
Staff member
Moderator
Mentor
#90
GG,

Welcome to the forum!

It's true that arrangement might add more strength, but a 10mm wide strip for a spar that long would be hard to cut accurately, where a stack of two 5mm thick strips will have a very consistent height.

This wing is plenty strong enough as it is. Go ahead and build it flat -- in this case it shouldn't be a problem. :)
 
#91
I maidened it and it flew very well.

I have a 60cm cf tube in my wing. But that is because it is made from 3mm foam and it is only taped in the center(so that I can take it apart for easy transport.).

http://youtu.be/B4BkpAyFsCM

Edit:
Oh I forgot to say in the video that I am running a APC 7x5 prop
 

ajlepel

Junior Member
#93
BTW, if you do make the power glider, turn on the break in the ESC. (not sure if Bixler mentinoed that in the build -- haven't watched the whole thing) A windmilling prop makes a lot of drag.
Craftydan.....could you please explain what you mean about turning on the break in the ESC? I'm not familiar with what this means.
 

Craftydan

Hostage Taker of Quads
Staff member
Moderator
Mentor
#94
ESCs have a feature called Brake (sorry, not break -- having them fail isn't a feature ;) ).

What it will do is short the three motor leads together, which for a three-phase motor, feeds the generated power from the coils back into the coils in the opposite direction (this is the gist, but the full explanation gets REALLY complicated). effectively the spinning motor has energy, the ESC uses that energy to reverse the motor and slows it to a stop. The motor will still spin if you try to turn it, but it will feel like it's magically resisting the motion.

The point is the spinning prop has a drag similar to the size of the prop disk. a still prop has the drag similar to the prop. Big drop in resistance by braking the prop. Even worse, a folding prop will not fold up if the brake is not engaged.

Brakes on ESCs are friends to power gliders :)


(as for turning the feature on, not all esc's have it. check the manual for that ESC to see if you can and follow the instructions to turn it on.)
 

daxian

Well-known member
#95
hi all ....
making this my first foam build,got the usual things/problems in the uk, i.e foamboard source and so on .
anyway ....i got all the parts together for a scratch build and i watched the build vidio several times and keep getting to the part of installing servo's in the fuselage where Mr Bixler says "install the pushrod on the first hole ,not counting the one we cut off " .

cant find any reference to cutting off the first hole ....maybe got lost in editing or something ????
is it really needed ??? where do i cut ? how do i cut ?
i will need to drill out one hole as the pin prick holes in these micro servo's are so flippen small i need to put glasses on to find them !!!!
any help appreciated .....
Dave.
 
#96
I do seem to recall they skipped over that step as well. Doesn't matter because it sounds like you already know what to do!

Take the straight servo arm and snip off the last hole. You can simply lay it on your table and use your hobby knive to cut off the tip. I typically cut right thru the hole to leave enough meat on the remaining hole in order to drill it out and still have support for the push rod. In this case, they want to be sure that the two servos don't bump into each other in the tight quarters of the fuselage so you might want to cut right between first and second hole. Use your judgement.

Like you, my push rod wire is thick enough that I typically drill it out with my smallest drill bit. Another trick I've seen is to use a short section of your push rod and chuck it up in your drill and just use the spinning push rod itself to drill a perfectly sized hole
 

daxian

Well-known member
#97
hi hack o holic...
thanks for the reply ....
i see a few inconsistancys in the build and the plans but i suppose its to be expected with the amount of work they put out
have to get some thinner pushrod ,only got 1.5 mm in long enough lengths ,will weaken the servo arm i think ..
thanks again
Dave
 
#98
I finished this plane last night. It was rainy and 30 mph wind, so not ideal for a simple soarer maiden. I took it out tonight for a few hand tosses, all I can say... WOW! This is a great little sailplane. I set the surfaces to neutral, and I needed no trim! I am using a 500 mAh 3S in the recommended location. I have a Turnigy 6A BEC located under the battery, with the receiver back near the opening in the bottom of the fuselage. I am running two HS-55 servos. I actually think this little plane would thermal! I may have to build a hook for the bottom so I can use my high start. I do know that in a light breeze, this would slope well. It's too light for higher winds, but in a 5-10 mph breeze, I think it would slope really well. I actually built it as a lift test for my Parkzone Ka-8. If this will fly well in the available lift, I am sure the Ka-8 will also. I just don't want to go around throwing my Ka-8 off of hills and cliffs hoping it will slope, so I build a lift testing bird!

The build does have some inconsistencies, but if you follow it generally, and look at how it has to lay out, it will work. I think I used .035" wire, or maybe .047" for the pushrods, and, and I used the outer sheath from some plastic control rods for the guide tubes in the fuselage.

I can't wait to get this bird on the slope! Or, maybe even in a thermal!

DSCN0569.JPG
 

daxian

Well-known member
#99
hi all ....
finally finished the build ....got some 1.2 mm pushrods and they work just fine ,being in the uk the foamboard is a bit heavier so all up weight is much heavier !! (620 grams !!!) thats with the power pod and a 500mah 3 cell .
had a tough time getting the cog in the right place and had to modify the fuselage to do so ,even tried a 2200 3 cell still no good,had to add 10cm to the nose !!!
(made a new fuselage) so i now got two ,the original i can use as the pure glider if needed.
not maidened as yet, but will soon weather permitting !!!


 
That's a real bummer about no lightweight foam board on your side of the pond. Mine, as a pure glider weighs 397 grams with a 3s 500 mAh in the nose. It's really floaty! I think it will still fly well at 620 grams, it will just have to go faster;)