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-   -   Great planes sprit 2m glider advice (https://www.rcuniverse.com/forum/rc-gliders-sailplanes-slope-soaring-112/11649019-great-planes-sprit-2m-glider-advice.html)

xxl 05-21-2018 06:15 PM

Great planes sprit 2m glider advice
I started with this plane along time ago. I never got it to fly good lost it due to a hi start fail. It didnt come off and it was dumped in to the ground. Since tower has been bought out i thought i d sang one up. I dont know if it will be produced any more. My question os should it be able to glide with just a gentle toss for flight trimming? Also what recommendations do you have for building it again. I want to get one that flys well. I think it was builder error that was another reason my frist didnt fly. Since this i have flowen rc planes and helis with out issues.

jamesef91 05-22-2018 04:53 AM

The Spirit is a wonderful flying sailplane. Just build and balance per the instructions and make sure that the wing panels are not warped during the covering process. To do so sight down each panel of the wing from tip end to root and for the inner panels make sure the airfoil cross sections are parallel and for the outer panels the same except that the tips point slightly down at the leading edge relative to the inner edge of the panel. A few gentle tosses will confirm no turning tendencies (check for warps and lateral balance) and correct cg. First flights off the high start can get exciting. concentrate on keeping the plane going straight and don't pull a lot of up elevator as it can stall. Maximum height can come later with experience. At apogee a slight dive followed by an abrupt pull up will help guarantee that the plane comes off. It is also important to check the tow hook for any burrs that could cause the tow ring to hang up and I have found it helpful to have the hook not quite parallel to the bottom of the fuselage. Opening it up very slightly will also help it come off tow. lastly not coming off tow doesn't have to be the end of the world. It has happened to me with an older model with an overly complicated tow system. Try the dive and pull up again and if it still wont come off just fly close in circles centered over the staked end of the high start and avoid getting close to the "end of your leash".
Best of luck

aeajr 06-02-2018 10:19 AM

The Spirit was my first sailplane. When I redid it I made several modifications. If I can find the thread on here I will add the link.
  • Changed from full size standard servos to mini servos. Today I would use HS-81/82 class servos.
  • Move the servos from under the wing to the rear most compartment under the canopy to shift weight forward.
  • Use Nylon push rods that ran along the edge of the fuse on each side. Worked great and left room in the center over the CG for ballast.
  • Drilled out a hole in the nose block and added an ounce of lead to move ballast forward
  • Sheeted the outer wing panels with 1/32 balsa on the top.
The result was a saving of about 4 ounces and a much better flying glider.

Also noted that the kit had a bit too much up angle in the h-stab. Hi-start launches tended to have the plane wanting to loop. So I reset the h-stab to a zero angle.

Finally I kept pushing the CG back and back form where the plans recommended.

I put HS-55s in each wing to operate the spoilers.

Result, a great flying sailplane. Still have it.

xxl 06-11-2018 03:44 PM

I just got it in the mail. Now looking into servos going with HS 82 and a small receiver Not sure if i want the spoilers. What battery pack works best in it?

aeajr 06-12-2018 07:18 AM

I would recommend including the spoilers if you can. Adds a nice level of control, especially in strong thermals and for landing in tight spaces. You can put spoilers on the gear switch, a two position switch, flap dial or on the left stick, in a similar fashion as to where flaps are normally placed on gliders. Left stick all the way up is spoilers closed. Left stick all the way down is spoilers fully deployed. If you have a flap to elevator mix, use that to mix the spoilers to the elevator. Spoilers usually benefit from some up elevator in the mix.

The Fuselage was designed for 4 cell 700 mah NiCd pack but I would not do that today. I would do 4 cell Nimh as you will likely need the weight to help balance it. RES gliders sip power so you don't need a huge pack. A cell 1200 mah pack or higher would be my suggestion. The 2.4 GHz packs draw more power than the old 72 MHz.

The HS82 is rated for 4.8 or 6V so a 2 cell Lipo might be too high voltage. If you want to go Lipo you will need a servo that is rated for higher voltage.

Hope that helps. Move the pack as far forward as Possible.

xxl 11-05-2018 07:28 PM

Thanks still waiting for free time to build it

xxl 11-13-2018 07:06 PM


BMatthews 11-14-2018 09:38 AM

You asked about tossing it for trim flights. It'll take more than just a light push but something less than an athletic javelin like throw.

What I like to do before I let it leave my hand is to jog into a decent moderate breeze and hold the model lightly at the balance point with just thumb and forefinger. Or even just standing in a somewhat stiffer but smooth steady breeze.

It won't be right at the flying speed but it's close enough. If should feel lighter and somewhat buoyant when the elevator trim and balance point are pretty close. If it still feels heavy then give it a couple of clicks of up trim until it feels light. If it is trying to pitch up and lift up and away then trim in some down until it is happy to stay put but feels light. This will get you close enough for the first test glides without giving a risk of nose diving or zooming up to an instant stall before you can find the control stick after the release.

Hope that helps out.

xxl 11-14-2018 06:10 PM

Yes it dose thank you

xxl 11-14-2018 07:32 PM

The wing joiner is super tight i did 1/16 and the 1/8 and the aluminum super tight any one else have this issue?

BMatthews 11-15-2018 12:30 PM

Are those the wire sizes for the wing joiners? 1/16 for the antirotation pin is fine. But 1/8 for a main joiner is really small unless it is only for the outer panels. Even then it's rather smaller than I would like to use.

A "trick" I've used for three models over the years is to leave the area that will house the slip tubes open at first. Then bring the two panels together and set them to the dihedral angles. Use long slip tubes that span the whole joint and take care to set them so they are as parallel as you can to each other looking from above and from the end of the joint line. After all the boxing in and potting in of the slip tubes is done cut them at the join line. The joiner rods should slip in easily now.

What happens if you don't get the slip tubes aligned well for center spacing and parallelism is the rods fit easily into each of the short tubes by themselves. But the slight differences in center to center spacing and any angular differences create a wedging effect and lots of binding. And I hate to say it but there's no good way to fix this other than by removing one side or both sides of one of the slip tube sets and replace it so things all line up better.

xxl 11-15-2018 08:30 PM

This the joined for two piece winghttps://cimg9.ibsrv.net/gimg/www.rcu...e9f0edb6c7.jpg

xxl 11-15-2018 08:31 PM

Also when sheeting the outer wing do you stop the sheeting at the spar?https://cimg2.ibsrv.net/gimg/www.rcu...826d5b66e3.jpg

BMatthews 11-18-2018 03:46 PM

You'll gain a bit of cleaner and more accurate airflow if you extend the upper sheeting about 1" past the rear edge of the spar. Doing so should perk up the slow speed flying by delaying or avoiding the often typical separation bubbles that can occur right at the edge of the LE sheeting when it ends right at the high point where the spar sits.

This was a common improvement done on some early designs that used the E205 airfoil.

xxl 11-18-2018 09:45 PM

Darn I only went to the spar

xxl 12-06-2018 07:04 PM

All done balanced took about 2 oz of lead to balancehttps://cimg8.ibsrv.net/gimg/www.rcu...8507b04ec3.jpg

xxl 12-06-2018 07:05 PM


xxl 12-18-2018 05:22 PM

Thanks everyone test gliding went well keeping it light it floats out of my hand

BMatthews 12-19-2018 12:17 PM

Great to read that the testing went well.

aeajr 12-26-2018 08:58 PM

Great news that it is flying well. Thanks for the update.

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