Spirit Kit - Any building advice?

[aeajr]

I just destroyed my Great Planes Spirit Select, an RTF package, that I have really enjoyed for about 60 great hi-start launches. I was learning how to use the club winch, got a bad launch, panicked, and put the plane into the ground very hard. Anyone need some tooth picks?

So I am going to build a new one from a kit. This is my very first kit, so I would appreciate any advice on building it.

Are there any pieces or places in the build process where I should deviate from the plans to reinforce the structure? I plan to build it stock, so I am not looking for modifications to the plans other than to improve the strength or to reduce the weight of the structure where appropriate.

I will be keeping the wing as a two piece wing. My habit was to tape the wing halves together with clear packing tape. The wings never fluttered on the strongest hi-start launches, even in 15 MPH winds. My NE Sail planes hi-start has 1/2" tubing and easily launches 3 meter+ planes. I get very powerful launches.

While the stab mount had been prone to breakage, it was easily fixed and I believed that this breakage probably saved the stab from damage. Sort of a sacrificial release point. Any thoughts on this?

Since I am still a fairly new pilot, I planned to stay with the rubber band wing mount method, but would be open to any alternate ideas.

Any advice on glues or gluing techniques?

Would I benefit from the addition of carbon fiber rod, tube, sheet, cloth or thread for reinforcement at key stress points?

Most of the time it will be launched using that powerful hi-start, but I am planning to do more and more launches using the club winch, so strength is important to me. I don't expect to zoom it, but since this is a new build, now is the time to consider reinforcement or enhancement to the structure.

I will be building in the spoilers using servos in the wings. I had recently added the spoilers in this fashion to the Spirit Select and really loved the way they helped with landings.

I will be covering the plane with Monokote.

Just for background, in addition to the 60 Spirit launches, I also have about 100 flights on an Aerobird electric parkflyer and about 20 flights on an Electrajet delta wing park flyer ARF foam kit that I built.

Thanks for any tips you may be able to provide as I start building my new sailplane.

[shaneyee]

Good luck...and be warned that this may lead to a life long addiction. Just a few words of advice...

1. Read the instructions and build it in your head. If it doesnt make sense, find out more... the instructions may be wrong, not up to date or the parts may have been changed. Great Planes' website may have updates...

2. Search this forum and the Charles' River Radio Controllers website. They have something on mods for this plane.

3. Once you've started....finish it.

Shane

[Doc Data]

I only flew the ARF and that aluminum/wood wing rod was very weak and eventually became the point of failure in a winch launch. A little gust of wind and I was flying the big 'V' into the ground! :rolleyes:

I'd recommend you replace it with something more substantial.

Dave

[Rob Nelson]

I've been flying a Spirit for the last five years and really enjoy it. It was my first sailplane at the time, and I built it completely stock. I have used a high start almost exclusively, with the odd launch using a winch. (with an experieced foot on the pedal I might add-not mine) I haven't had any problems.
I did have a rather firm landing once upon a time and the wing joiner had a few cracks and a minor delamination. Had no damage to the joiner boxes..Rebuilt the joiner and was flying again.
If I was building another one I would not use the supplied spar webs. I would make the webs the thickness of the spar(vertical grain) out to the poly break..then step them down in thickness to the tip (1/16"). I'd use kelvar thread to wrap the joiner box as per the plan, but would continue out to the poly break with thread spaced further apart. I'd say 1/4", but I'd pay attention to comments from the more experieced guys here. I'd also consider continuing the top sheeting to the wing tips and the bottom of the main wing panels to the main spar (slice 1/16" off the bottom of the ribs from the spar forward). I would just use music wire notched in at the TE near the fusalage instead of the ply wing protectors. All this being said...try to keep it light.
Some great ideas at this link...
http://www.charlesriverrc.org/articles/kitmods/dickwilliamson_gpspiritmods.htm
Good luck with the Spirit.
Cheers,
Rob

[rdeis]

I put two strips of 1/4" carbom tape on the inside of each fuse side. If I remember correctly, the tape was applied to the full length fuselage side before the doubler sheet. The tape runs all the way from nose to tail at the top and bottom edges of the fuse. This is a small effort, and a big strength bonus.

If you can, get micro radio gear and install it in the nose under the canopy just behind the battery. This will move your CG forward so you need less lead in the nose to balance- dropping overall weight. There's a good picture in another thread on this forum.

Last thing I did, you probably won't: Added 3/8" corner stock as longerons from nose to tail on the bottom. This would add weight, but I then shaped the bottom corners of the fuse to be smooth and round. I actually ended up removing the entire glue joing between the fuse bottom and sides- the corner stock does all the work. It comes out looking nicer, adding strength, and reducing weight (and maybe reducing drag some, too). But the sanding/shaping is a lot of work.

My Spirit got shot down by radio interfearence- spun in from 100 ft. The wing shattered, and the radio gear broke from it's mounts and fell out the canopy.

With the carbon, though, the fuse and tailfeathers remained fully in tact. I'll eventually build a new wing and be back in the air.

[sierra-gold]

aeajr,

While building the fuse you might want to consider adding an antenna tube. This can be made of lightweight plastic tubing or even soda straws spliced together(to save weight) running from the wing TE bulkhead, aft to the fuse tail. Glued to the inside of the fuse it makes an easy way to contain the receiver antenna. Just be sure it's large enough diameter to easily push the antenna through. The excess of the antenna length just hangs out the back of the fuse.

On a large enough glider, the antenna can be contained in the tube.

Sierra Gold

[aeajr]

Thanks everyone for the advice. I hope more people will comment. I don't fully understand all of it though.

rdeis
Do you have a source for this tape? Where exactly did you attach it? Down the center of the sheet? At the seam to the bottom?

As far as micro gear, how do I know how small the gear can be? Is there spec on how much torque the servos must have? I don't want to get into a dive and not be able to move the surfaces.

The RTF came with Standard servos, CS-61s that are 1.8 oz each. I was going to change to GWS servos at .86 oz each and try to move them forward as you suggest.

Also, I built a great planes power pod for the original spirit but never used it because the servos were right over the CG which meant I could not put the battery there. I was going to move them, but the spirit died first.

So, I plan to try and keep the area under the wing, on the CG clear so I can place the battery for the power pod there without having to rebalance the plane each time I put the pod on and take it off.

Any thoughts on this?

[rdeis]

I got mine from the LHS. There are several online vendors that carry thin strips of carbon fiber. IIRC the fuse sides come in two pieces, a forward half and an aft half. You join these two, then put a second piece on top to double the thickness under the wing saddle. Place the carbon along the inside face of the fuse side after joining the two pieces, near the top and bottom edges.

I used Cirrus CS-20 servos with no issues. Had a third one mounted in there for spoilers.

[rdeis]

Originally posted by aeajr
So, I plan to try and keep the area under the wing, on the CG clear so I can place the battery for the power pod there without having to rebalance the plane each time I put the pod on and take it off.


That space is clear in mine. The battery pack will center behind the cg, though, so you'll prolly still have to rebalance. Depends on the size and type of battery.

[aeajr]

Originally posted by rdeis

I used Cirrus CS-20 servos with no issues. Had a third one mounted in there for spoilers.

I looked at the specs on the CS-20. These only have 11 inch/oz of torque and weigh .3 oz I would have feared going this small.

The orginal servos had 42 oz of torque at 1.75 oz wt.

The GWS I was going to are 47 in/oz at .8 oz. I already have these, but if I feel the need to go smaller it is good to know I can.

Has anyone else gone this small on servos on the spirit or similar planes? Any advice or concerns?

Thanks.

[Ollie]

Micro servos can be made to work under certain conditions. The control surface hinges must be low friction. The pushrods must also be nearly friction free. Hard landings and crashes can put great inertial loads on the servo gears stripping them. Therefore, the pushrod assemblies and control surfaces must be light weight for the servo gears to survive an abrupt "landing." Mini servos like the JR341 have more than adequate torque and are light weight yet have very strong gear trains. Quality like this costs more though.

[Soar_dude]

If you go with Micro gear I would go with a Hitec HS-81 32oz of torque or a HS-85 with 42oz of torque I would not go with anything Lighter or lower torque you run the risk of overpowering the servo during high speed manuvers ie, spinning to get down from alttitude. with the lighter gear you also run a greater risk of stripping the gears in the servo if you try and make them move to big of a surface. It is better to err on side of caution and be a little over weight then lose control of a aircraft trying to keep weight down!

Soar Dude

[rdeis]

Fir enough- just because I got away with it doesn't means it's a good idea. I should mention that mine is build with a V tail and has lower total tail area than stock as well, with tape hinges-- a lot of folks have reccomended *increasing* total tail area, especially fin area, for better stability, yet mine flew beautifully. <shrug> I spent some time looking at stability charts before deciding that was OK, but I'd have to do it again to explain why I figured it would be OK.

I'd say that the most important thing about servo selection is size rather than weight, meaning that if you can fit them up under the canopy their weight contributes to balancing the model, which means less lead. This makes a bigger difference in weight than you'll get from just using lighter gear. If you have several to choose from that fit, then you might consider weight. The Cirrus 4.9s have 14oz-in at 4.9grams. Egad.

In my particualr crash, the radio gear mounts (a relatively thin lite ply tray I made) failed and the radio gear was ejected undamaged. I've since used it in a 60" fairly hot V tail HLG and a 30" park flyer. Both planes are happy.

I know a guy that is using 8oz-in servos in flaperons on his Formosa, and he flys it fast and in patterns. We're at high altitude, though, which reduced the flight loads a bit. Your airplane- your call.

[rdeis]

Is this a spoiler wing or the aileron wing? If spoilers:

IMO the stock spoilers are too small they'll spoil lift OK, but don't give you any braking effect. I extended mine 2 bays outboard and one bay inboard.

Consider installing a larger tube for the servo cord- a couple of people on the forum have decided to retrofit individual servos in place of the cord and had trouble routing the servo wires back to the fuse.

[FlyingPig]

I'd rather move up to the Spirit-100 if you don't have size constrain. It has better airfoil which should help solving the wind penetration problem in the Spirit 2M. You can just tape the airelon together if you want to stick with RES. I'd buy it if they had the ARF version since I don't have enough space at home to build.....

FlyingPig.

[aeajr]

As always, you guys provide great info.

1) I started one of the threads on putting wing servos in a spirit and did it successfully, then trashed the bird. Larger tubes is a good recommendation

2) I will go with an HS-81 class servo. The point of putting the servos forwad to help with balancing is a really good point. I was doing that, but for a different reason.

3) I am not ready for the spirit 100. I have he spirit 2 meter kit on the way and will build it res. I will probably put the servos in the wings Since that is what I did last time. However the Spirit 100 is on the radar for the next plane.

The idea of extending the spoilers little is a good one. I might do that. Would that raise any stress or strain concerns? I have no idea how one sizes spoilers. Can they become too large having an adverse effect?

What is this about expanding the tail? Should I be doing that?

I still have the tail from the original bird. It survived the crash, so I can have a stock fin/rudder/stab/elevator ready to go. I can build an expanded version as well and interchange them.

Would I need to build up the back of the plane to handle the larger surfaces?

[Soar_dude]

Kinda off topic but you would like the Spirit 100 better then the 2 meter. One you get more hang time with the 100 then the 2meter. Easier to see way up. You also can build the sport wing with spoilers then get the lumber and build the advanced wing since it comes with 2 rib sets for each wing. The only drawback is that it does fly a little faster then a the 2meter. I have a 100 it is stock and it flies real nice for me I working on a streched advanced wing right now. The 100 is nice transitional plane for going to a full house sailplane.


Soar Dude

[aeajr]

Soar Dude

You are right about being off topic, but I do appreciate your thoughts.

I am seriously looking at the 100 for my second sailplane. I have been put off because it was not availbale ARF, but if the build on the Spirit goes well, that may not be an issue.

I am also looking at the Marauder, a 115" RES sailplane. Know anything about that one?

In either case, I want to build the 2 meter because that is what I had. I have the remains of the original as a partial reference model. I may learn enough, building the new one, to repair the original fuse and build a new wing from scratch. Why? Because I think I want to.

In any case, I am grateful for any tips on building the Spirit 2 meter for right now.

[rdeis]

Originally posted by aeajr
As always, you guys provide great info.
3) I am not ready for the spirit 100.


You're more ready than you think. Bigger airplanes fly better, plain and simple. They are easier to see, more efficient, and (all else being equal) more docile. That said, sticking with what you know will get you back in the air fastest.


The idea of extending the spoilers little is a good one. I might do that. Would that raise any stress or strain concerns? I have no idea how one sizes spoilers. Can they become too large having an adverse effect?

I suppose you can, but I haven't. In any case, it's easier to make them smaller than larger. IIRC my dad decided the 1/2 span spoilers on his Legionaire were a bit large, so he cut part of them off and taped it down.

You could have an adverse effect if open spoilers shadow the stab, so keep them outboard.

I think it's a style thing-- The way I fly demands very large spoilers. The way others fly may not.


What is this about expanding the tail? Should I be doing that? I can build an expanded version as well and interchange them.


Don't know- I've seen others reccomend enlarging the fin. I've not seen it done around here so I can't comment. It's possible that my V conversion traded stab area that isn't needed for extra fin area that is? <shrug>

Exchanging them would be a great test. If you're in a science project mood, you could build a V as well, then fly the version that does best for you.


Would I need to build up the back of the plane to handle the larger surfaces?

Doubt it, it's plenty strong back there. You might have to do some work to make it exchanging tailfeathers a simple task, though. Watch for weight gain- ever ounce you add back there is 2 or 3 you have to add to the nose to balance.

[Soar_dude]

Normally on the 2 meters the spoilers are made from the same size trailing edge stock as the wing (at least from all the kits I have built) which is normally 1" wide and goes 3-4 rib bays long (rib bays is the space between the ribs). Where to put them though usaully mid way out on the inboard wing painels if it has a center diehedral, if it is a flat inboard panel then I have only seen them in the center.
The Spirit series have adequate spoilers for the job. They could be made bigger to give you the putting the brakes feeling.
I used to fly and old Global Easy Answer that I put barn doors on they where WAY overkill for a 2 meter but I never lost control of the glider when I deployed them. They just made my descents very very steep. Rdeis is right about what makes you comfortable. You mentioned Merrills Maruader that plane has both top and bottom spoilers I have his 2 meter Grand Illusion it also has top and bottom spoilers. Talk about putting on the brakes what makes that system nice is that you do not need to put in any elevator correction when the spoilers are deployed. Merrills designed the wings on his gliders to withstand FULL petal on the winch I can attest to this having seen him full petal his prototype Maruader, and I have full petaled my Grand Illusion many times with no probems whatsoever.
But here I am wandering again. Rdeis mentioned Carbon fiber on the fuselage I would also epoxy Carbon fiber on the bottom of both basswood spars before assyembling the wings this will greatly increase the strength wing I would also put some shear webs that are the width of the spar going out 2 bays from the spar joiner this will help transmit the load the spar joiner is taking.
I would also sheet the front part of the outboard wing panels with 1/32" balsa this will keep the monokote (or whatever covering you use) from saging between the ribs on the leading edge this restores the correct airfoil shape making it less prone to tipstalls at low speeds. Build the tail LIGHT look at the wood that comes with the kit Great Planes has a habit of sending HEAVY balsa in there kits I know this my Spirit 100 came with a TON of it I have heard that the people have enlarged the rudder surface area by 50% Seemed like alot to me. I have also heard of people doing the V tail thing and like it. The only thing I did different on my Spirit 100
was make it with a split rudder to improve turning now Ollie is going to speak up saying that it causes more drag, but I have not noticed this problem. Make sure there is zero incidence between the wing and horizontal stab(incidence is the difference in horizontal angle between the wing and the stab).
The reason this is so important is that at higher airspeeds the glider will want to pitch up and slow down. The Center of Gravity recomendations on the plans is TOO conservitive. We eneded up taking 3oz. of the 5 my friend had in his Spirit ARF and after that it flew a whole lot better for him.
Heres a pic of my Spirit 100
Soar Dude

[aeajr]

Great ideas folks. I can't thank you enough.

[rdeis]

Originally posted by Soar_dude
Carbon fiber on the bottom of both basswood spars before assyembling the wings this will greatly increase the strength wing


I thought about that- I built the wing one piece and have continuous strip from one side to the other, it extends about half way out the tip panels. I wasn't sure how much benefit that would be on the two iece wing since you have to cut it at the center joint, where stresses are highest.

I would also sheet the front part of the outboard wing panels with 1/32" balsa this will keep the monokote (or whatever covering you use) from saging between the ribs on the leading edge this restores the correct airfoil shape making it less prone to tipstalls at low speeds.

You can address this with washout as well, easier, little bit lighter, but not quite as effiecient.

Make sure there is zero incidence between the wing and horizontal stab(incidence is the difference in horizontal angle between the wing and the stab).

I'd not worry *too* much there, as long as the wing saddle is flat- build to the plan. He's right to say that incidence is important to flight, but with a rubber-band or bolt-on wing it is very easy to adjust after the fact by adding shims. Incidence is a tuning thing to me, as the correct incidence depends on CG, which depends on the pilot's style.

That can be a long discussion- but the jist is that if after you have the cg set and the plane trimmed for level flight, the elevator isn't parallel with the stab, the incidence is wrong.

[RSCherry]

One other thing to consider if it has not already been mentioned- cover the bottom of the wing in a dark color (black, dark blue, etc), top in a light color (white, yellow, etc). This really helps visibility when you get way up in a hat lifter. This included the stab too.

[aeajr]

thanks for the color recommendations.

The original spirit was white on the bottom and white and red on the top.

I was planning to missle red on the bottom and red and white on the top. I will put some kind of stripe or something on one bottom wing to help identify direction up high.

[RSCherry]

You probably won't see the stripe at altitude- every bottom color seems to look black (including white) when you get high enough, since it's all in the shadow of the wing.

[aeajr]

my spirit had a stripe on one wing of about 12 inches in width made of alternating black an yello sitting on the white wing. I could see it quite well at a pretty high altitude, perhaps 1000 feet and 1000 feet out.

If I put a white and yellow stripe against the red underside, I think it will show.

We will see.

[aeajr]

This thread is old, but I would like to revisit.

Turns out the original spirit was not as bad as I thought. I have been rebuilding it. As an aside, I ended up buying a 3 meter full house from another club member so the spirit 100 idea was dropped.

Before I put the covering on, another pilot said that if I sheet the front of the wing outer pannels, same as the inner panel of of the wing, that it helps eliminate tip stall.

I am finally up to the point where I can re-cover the wings. I am going to add the 1/32 sheeting to the outer panel of the wing. Do I just lay it on top of the ribs or do I overlap onto the leading edge? Any thoughts on this?

I thought I would just lay it on the ribs with a little overlap onto the leading edge, then sand it to blend it into the leading edge.

Does that seem reasonable?

[colin wavell]

Why not just build the Spirit Elite...Its less draggy and uses small servos. I built the full house version and it makes a great trainer for a novice computer radio full house pilot. Best glider I've built and I've built a few. My only grone is the the roll performance could be better...but you can't have everything in one plane. It flys great of the bungee and is great on the slope

[aeajr]

colin wavell

Colin, as it turns out, I am not going to bulid anything. I am repairing my original spirit. The sheeting question, two posts up, was related to the wing that is under repair.

[Soar_dude]

Aeajr I would gentle sand down the ribs between the spar and the leading edge until your sheeting fits flush with the leading edge and the spar. You do not need to sand off very much to do this. You will notice a improvement when comes time to do turns.

Rdeis: Efficency is what this sport is about. The wing incendence is important too yeah you can shim the wing up, but now you have more drag with a shim under the wing and rest open this allows the slipstream to try and tuck under the wing saddle. Also with shimming the wing you change the attitude the fuselage is flying at and that will also create more drag with more frontal area presented to slipstream. Incedence has nothing to do with C.G. it has to do with drag and haveing the glider flying straight through the air with no nose up or nose down attitude.

Soar_dude

[aeajr]

Thanks for the Advice Soar_dude. My concern was that I might change the shape of the airfoil. While the 1/32 sheeting would raise the hight of the foil, it would not change its shape.

Or am I mistaken?

If I sand the ribs, I will try to preserve the shape of the airfoil.

[Soar_dude]

Only sand a little bit at a time. A trick I use and works well for me is to take a Sharpie maker and make run it over the edge of the rib. the ink transfer's into the balsa a little bit I sand it down till the ink is gone I did this trick on my spirit 100 ribs worke like a charm I took off enough material for the sheeting to fit and did not distort the airfoil.

Soar Dude

[aeajr]

Good idea

[aeajr]

As notec before, I am rebuilding my Spirit after a bad crash off a winch launch. I added servos into the wings to operate the spoilers, just before the crash. They work very well, and managed to survive the crash.

In the process of doing the rebuild, I am making some changes to the plane.

My original interior layout required about 4 oz of lead in the nose to balance
it. As part of the rebuild, I embedded about 2 oz of lead in the nose block
to get it out of the balance compartment.

I also have moved the servos forward into the receiver compartment. The standard size servos just fit side to side and in height. This should reduce the amount of balance lead I need.

I am switching to golden rod control rods for the elevator and rudder so I can run them along the sides of the plane. The standard control rods run down the center. Between this and the move of the servos, I have opened up the space right over the CG, under the wing.

The reason I did this is that I built a GP electric power pod for the Spirit
so I can launch it electrically at times, but keep it primarily unpowered. By
moving the servos forward and running the control rods along the sides, I can place
the battery directly over the CG. Hopefully this will minimize or eliminate
any need for rebalancing or adding balance weight when I put the pod on and off.

If you are building a Spirit, and haven't committed the position of your components yet, you might give
these little changes some consideration for the flexibility they provide.

[aeajr]

Have you ever considered sailplanes?

If you read through this thread because you are thinking about sailplanes, I hope you give it a try.

It is a different flying experience that is very addictive. Flights can be measured in minutes, but they can also extend for over an hour. Every flight is an adventure and every flight is different.

No fuel, no noise an no washing the plane down
after the flight. It is a hunter's game, if you are up for it.

Sailplanes are wonderful
http://www.rcflying.net/forums/showthread.php?s=&threadid=5356

If you are interested in what it would take to get started in
sailplanes/gliders, visit this thread:
http://lisf.proboards13.com/index.cgi?board=general&action=display&num=1070740602

[aeajr]

I think the spirit will come out better after the repair then when I started. If you are interested, here is a link about it: http://rclibrary.com/viewtopic.php?t=127

[aeajr]

The rebuild is done. If you are interested, you can read about and see the final results here:

Making the best of a crash
http://www.torqueroll.com/forums/showthread.php?s=&threadid=2473