Another way to fit the battery in the engine compartment is to bolt your engine in place with long screws, then add a plywood platform to the back sides of the screws. Clip off any excess threads, add a foam block, and strap the battery to the platform

thanks guys for thebattery mounting tip. I just maidened my new Skybolt! I have an OS .91 2 stroke with JR electronics. I added the Sig tail wheel and I am using 2 elevator servos instead of one. I needed 1/2 lb of nose weight with the battery in the middle of the plane. I am looking forward to moving the battery forward and getting rid of the lead. What prop are you guys spinning with my engine setup? I flew with a 15-8 tonight. The book for the motor doesn't list a 2 bladed prop smaller than 15". The write up on Towers site lists about 10 props all the way down to 12 or 13 ". They recommended a 13-8.. Any comments?

I originally had a 15x6 on my plane which has the O.S. .91 Surpass III.

I had e-mailed OS about my O.S. 1.20 Surpass III FS Pumped, because I was not seeing the power output I expected, and they wrote back and told me to FORGET about recommended prop sizes and prop the plane for RPM's in the 9000 range.

They said the I usually needed to go one size down on the prop to achieve this.


Sure enough I went with the 14x6 on the O.S. 91 Surpass FS and the plane got a LOT of power.

TRY IT!


As for the weight at the front.

Initially I put a spinner weight on mine, then moved the battery as far forward as possible, and moved the engine forward a tad to get the plane balanced.

It flew nose heavy at the recommeded C.G. range.

Move the battery as far forward as you can in the existing compartment, but don't go as far as I did.

Start taking off nose weight 1-2 oz at a time from the nose and fly the plane after each change.

If it doesn't get too "squirrly" on you and seems to SLIGHTLY nose down on 20-30 degree turns, you're good. Otherwise keep at it until it behaves like this.

If it wants to nose up, you've gone too far, and should add more weight.

Once you have it not nosing down, fly it inverted for a few seconds to double check.


I'll bet you end up taking off ALL of the nose weight ( I did! ) and leaving the battery exactly where you have it now.

On the kit version, the battery has to go as far forward as possible. It's sheeted balsa all over the plane with no lite-ning holes. No wonder it's a heavier plane than the ARF. MM

Hey guys,

Been following the thread for a quite sometime, and now that you guys are posting again, I decided to fianally picked up my Skybolt last Friday, and boy, did I get a bad one. Covering was terrible, parts missing, etc, etc. I am going to contact Great Planes and see if they can help me out.

I am going with the an OS .91fx on mine, and I am going to do smoke. Sounds like maybe the 14x6 sport prop is the way to go. I think I will start with that and see how it performs. Going to start out with the CG at the aft most suggested, and see how it goes.

Couple of questions:

Did you guys use one elevator servo and set it up per the instuctions?

Does your red checkerboard covering seem thin, snd shrink a lot under heat?

Anyone mount the control horns on the lower wing with more reinforcement, or are 2 screws good enough to hold both ailerons on each side?

Any other mods that you guys would recommend? Landing gear need any reinforcement, etc?

Thanks,

Adam

I set mine up per instructions.

Not really. It's held up well. I initially took an iron to it to tighten it, but that's about it.

I haven't had any problems with the setup as recommended after many flights.

I liberally applied epoxy around the gear area and added a hardwood piece.

I would also see about adding some re-inforcement to the firewall, as others have posted that there is not much securing the firewall to the fuselage.

I just finished mine and only have about 5-6 flights on her. I used the Sig small tailwheel instead of the stock. I didn't modify the main gear or structure around the gear. I noticed a post early in this thread about some aftermartket main gear that is 2" taller to use with the Sig tailwheel. I still have the main stock gear on and it sits a little flat but it handles, takes off and lands just fine. I did use 2 elevator servos. I just offset the rudder linkage and faced the rudder horn towards the outside like the throttle. I then faced two servos inboard for the elevators. So the end result is spreading the servos out as close to the outside edge as possible. I can just barely see light between mine. I also used robart servo horns! I am placing the battery on the engine mount as per illistration above. That should make it be real close to the forward most CG point. BTW I maidened mine with the CG very close to centered. It felt nose heavy. I think I picked up in this thread that the CG can be moved forward quite abit to make her more tail heavy.

The kit was complete and in good condition. Small stress crack on the cowl and the covering of course needed tightening. Monocoat is thinner than ultracoat if you are used to H9 ARF's.

I am going to expirement with a few different props on my .91FX I had bought the engine for another plane and it was to small so I don't have much time with the .91 The write up on tower recommends the 13/8 for raw bench power. I am going to try that next time out. Along with a couple 14" props. The spinner sure wont fit a 15 or 16 inch prop I have a custon cut tru-turn spinner I am using now. It is 1/4" bigger. I would like to save that for the propsize I had it cut for and use the kit spinner if I can.

I'm using an OS61 and have no regrets. I usually fly OS91s on 60sized airplanes for the extra power, but this ARF is about 2 pounds lighter than the kit airplanes were. And mine came out to be 7lb 4ozs so the 61 with a 13x6 has little to pull. It's a biplane and they usually aren't going to go any faster with more power. And it's not 3D capable.

One and it's ok.

It's definitely not your normal Monokote. Mine has already been cut in a number of places on the stab from FOD. Monokote has stood up to the same field conditions on my other airplanes, so yeah, it seems thin. I used an iron and didn't notice any difference.

No need for increased strength if your aileron wood is firm enough. I did change the mounting scheme as shown in the attached pictures. The rigging they provided will cause different aileron deflections top to bottom and the differences will even differ from UP to Down. And what I did was easier too.

The gear support from the fuselage is actually strong enough. The main gear itself isn't, at least on mine. And it's about as short as it can be and still be "adequate". I fly off of grass that is cut weekly, and my 13x6s are green tipped now. And I have to bend the gear by hand every so often. I've looked around for stronger, taller replacement, but it's a uniquely shaped and sized gear.

I did a boo boo with mine awhile back. Basically landed it somewhat hard out of a flat spin.

The motor mount center punched the firewall cleanly. The cowling wasn't even messed up, but the firewall had a neat, clean hole completely through it. It is made of two layers of LITEPLY. No lie.

LitePly is quite variable in quality. Firewalls ain't where you'd want to use it in a manufacturing environment with workers who have no understanding of wood selection.

If I put together another one of these ARFs, I'll probably layer some AirPly to take the compression of the motor mount bolts on the inside, and to take the stress risers around the motormount/firewall line.

I autopsyed another plane yesterday that had a LitePly firewall. We'd noticed the engine/mount flexing under the starter load and were planning to check that firewall. Got the opportunity to see it close up. It was crap LitePly. $300 ARF with two layers of crap liteply.

Thanks for the detailed answers. I think I will reinforce the firewall while I am at it and hit the landing gear area with some epoxy. Sounds like the 2 screws for the lower wing control horns are not a problem. I removed the screws and wicked in some thin CA per the instructions, so I will consider it good.

I should have it ready to go for this coming Sunday. I am going to get a few flights in before I add smoke.

And personally, I really like the stock tailwheel. In fact, I liked it so much that I bought two more to use on future projects.

I tell the wife i got to have SPARES in case of a dumb thumb !!!! great deal i would have bought it to .

Don't worry too much about getting that area covered too heavily. The entire forward fuselage inside on all my airplanes get a thin coat of polyurethane or epoxy surfacing resin and from what I've seen of this airplane, that's absolutely sufficient. The aluminum gear is really not rigid enough to beat any stress into the fuselage. And the gear is also about twice as large where it mates to the fuselage bottom compared to most. Heck, it might be 3 or 4 times the area of most.

I've considered that if I needed to build another, that one's aluminum plate gear would either be retrofitted or........ It might get a single piano wire gear that mates flat against it and doubles it. It's actually almost stiff enough on it's own. If aluminum could be retempered, I would have already done just that.

About the only thing close to being "wrong" with this gear is that it's just too short for what a bunch of people seemed to automatically wish to do, plug in a lot stronger engine.

Hey, Minnesnowta is dead right about that tailwheel. Don't overlook his advice in all the detail in this thread.

That tailwheel is great. And I did just what he has done. Ordered a couple to go on my next planes.

Well I put her on the scales once balanced without weight and she weights in at 7lb 9 OZ.

I forgot to mention my most important mod...the pilot. My pilots name is Pamela. I could of swore she was a slimline extreme pilot but she is not on their site and I threw away the pkg. Anyway by the shape of her figure I would guess her last name is Anderson I wish I hadn't broken my digital camera.

Picked up a dozen myself... gotta like the price!

Running a YS 110 on mine with a three blade 14 X 7 Master Airscrew prop. Got plenty of ground clearance with the stock gear.

If aluminum has been heated or welded resulting in a loss of temper it can be 're-tempered'. Repeated bending makes it harder/brittle due to work hardening and will, over time, result in a failure. The stock main gear feels a little soft so it does not seem to be 6061 T-6 as it should be. TNT probably makes or will make a stiffer and/or taller gear for those interested.

Devens,

You will have to report how the different props do on the .91fx. I have the same engine, and am eager to hear which prop performs best for you. Are you using a Slimline Pitts muffler?

Question:

Been doing some research on smoke systems and I have heard that some guys are using a needle valve on the inside of their muffler to disperse the oil in a fine mist for better smoke. Anyone tried this? If so, what kind of needle valve are you using. I was thinking about calling Slimline and seeing if they make anything for this.

I had posted that my Skybolt was in pretty tough shape when it arrived, and that I was missing some parts. I am happy to say that I called Great Planes and they are taking care of everything. They are sending me some new parts and a new lower wing. The lower wing was the only thing I was unable to fix. Kudos to Great Planes excellent customer service!

Danifino - Great looking Skybolt! Those are the best mods I've seen on this plane. Even the 3 blade prop looks scale instead of big and cartoony. Great job!

can you guys point to a link as to where you got the tailwheel assemblies?
i can't find them, and would sure like to get a few myself.

adam,

Yes I am using a slimline muffler. I will let you know on the prop.

Sure [link=http://www2.towerhobbies.com/cgi-bin/WTI0095P]CLICK ME![/link]

http://www2.towerhobbies.com/cgi-bin/WTI0095P



A whopping $1.89 USD!

If it doesn't come up search for GPMA2838 at Tower.


EDIT: Seems like Tower doesn't want people linking to that item... use the SEARCH instead.

thank you thank you.....got it

i couldn't find it to save my butt...........wonder what else they have in hidden corners?
maybe the Futaba 9C in 2.4Ghz....LOL

Actually, Sullivan offers almost the same tailwheel with the same design, only they offer a range of them for different size/weight models.

there is a 2-6lb airplane one,
here is the 5-12lb airplane one http://www2.towerhobbies.com/cgi-bin...?&I=LXFV47&P=7
there is a 10-22lb airplane one,
and a 16-25lb airplane one.

But the Great Planes one is more than excellent for $1.89 for 5-10lb airplanes. http://www2.towerhobbies.com/cgi-bin...38&FVPROFIL=++

I'm using a Sullivan Smokewriter with a homemade brass tubing preheater. Makes lot of smoke with my YS110. The smoke nipple is within 3/8" of the exhaust port, where it's the hottest. Pictures of the installation are in this thread on page 6, post #113.

Thanks SKORMAN. It has around 25+ flights on it now and I really like it. Landings are beautiful, power is unreal.