GP Super Skybolt Crash Purchase
 

I recently attended a local HS swap/ shop, and was walking thru the area looking at what was for sale. Well, I happened on a GP Super Skybolt fuselage sitting under a guys tailgate, and saw that the firewall was missing, and broken out. The canopy had $150.00 taped on it, so I asked the fellow if that was all he had of the plane. He said "No", and the rest of the plane- wings, struts, and hardware was all inside the truck. I asked to see the wings and rest of the parts. Well, everything else was in perfect condition, and not a scratch or wrinkle on it anywhere. I picked up the fuse to look at the extent of the damage, and saw that the 1st 3 front formers, and firewall was pretty well knocked out. I asked him what happened, and he said he pulled the plane up before he had enough ground speed, and may have had some right aileron on the right stick, instead of holding the right stick at a true position, and the plane ground looped. He had an OS 91 4 stroke in it, and it went through the firewall, and back to the 2nd former. It also had enough shock that the impact knocked the servo tray loose.
Well. I pulled out a $100.00 bill and made him a offer for the C note, and he said the servos that were in it were worth more than that. So I told him I didn't need the servos, and take them out. He said he didn't have any tools, but would think about my offer. I walked away, and when I was about 10 feet away, he called me back(after his buddy prodded him), and said he would take the $100.00. So I paid him. picked up all the parts, and loaded them into my van.
Later that evening I decided to see what it was going to take to make the necessary repairs. After looking everything over, I figured what I would do.
The following is what i found, and repairs that i started: Dean http://static.rcgroups.com/forums/im...s/confused.gif

I took out a few tools, and some hardwood planks, good "American" aircraft ply(different thicknesses), some hard balsa strips, and some balsa sheets, and my Zona saw. I trimmed out the broken parts of the upper formers, and cleaned out the front fuselage cavity, and made my approach to how i wanted to make the repairs strong, but more feasible for access to the front structure. While making my visual observations about how the Chinese construct these planes, I thought i would at least add a lot more structural integrity to the front, and improve anything else that i would find inside the fuselage.
I had already started some repairs when I decided to do an article and show some pics of the repair process.
After doing all the trimming of the splintered formers, and cleaning out the fuse cavity, I glued in 2- 3/8 X 1/4 hardwood braces across F2 and F3, glued a piece of 1/8" balsa sheet, and decided to use that as the cradle for the new tank. I had to cut a new piece of support for the lower front of the firewall, and epoxied in a 3/16 ply plate at the bottom, and had to trim and clean up the upper part of the damaged firewall, and epoxy in a 1/16 piece of ply there to make the firewall support flush with the rest of the front.
I decided that i would add a little structural support to the sides of the fuse between the firewall, F1, F2, and F3 on both sides.
I'll continue on the next post-- Dean

I took out a 12"X12" sheet of 3/16 ply, and outlined the replacement firewall, and cut out the piece I would need to start with, and proceeded to trim and shape it to dimension. I thought I better call Tower Hobbies, and order a cowl so that I could continue with engine mounting position. While I was waiting for the cowl to come in, I took another overall look at the inside of the fuselage cavity. I noticed that the top of the front fuselage was balsa sheeted, and looked at the inside upper portion. I saw that there was a foam core sheeting under the balsa. I'm lucky that when this was crashed, it didn't accordion the foam part. I decided that i would add 3 hardwood stringers on the roof of the front fuselage for added support and strength. I epoxied in the stringers, from the firewall to the cockpit dash.
The cowl came in and I did a trial fit over the new firewall. I had to do a little more trimming, sanding, and shaping on the corners for a perfect fit. I measured and marked the center of the firewall, and installed the motor mount blind nuts. I slipped the cowl on, and measured from the firewall to the front of cowl, and needed to add another 3/16 block to the rear of the motor mount for correct distance for prop.
I mounted the firewall and motor mount to the fuse, and wanted to trial fit the cowl so i could drill the necessary holes for the glow plug, and carb needle. I'll continue with the next post. Dean

100 bucks for all of that was a great deal.
Very clean rebuild as well!

Crash Find - Skybolt
 

Finally able to get back to this repair. After looking this over again, I didn't like the tank pictured, so I opted for a different tank, and wanted the fuel lines to come through the firewall, as I want the firewall to be a removable unit. I assembled another tank, and had to do some bending and shaping of the brass lines to fit the firewall holes. I drilled the upper part of the old existing piece of firewall, and screwed the new firewall in place. I got inside the fuse, and marked the new hole location on the new firewall, and drilled it out. I reinstalled the tank, and checked the fit of the brass lines. So far, so good. I have to reinstall the servos again, and make up a new throttle rod. I'll do that later.
I removed the canopy, and didn't like the way the cockpit looked, with all the bare balsa, and decided to make it look at least a little more scale. I painted the inside cockpit with flat black paint, and added an instrument panel. I needed a pilot, and had a few, but they were just a little small for the right look. I went on Ebay, and found a neat looking pilot just the right size, did a little trimming on the base of it to get it to fit under the canopy. after trial fit, I painted the jacket, and shoulder belts, and glued him in place. With the canopy reinstalled, the plane looked much better.
Since we have a grass field, I removed the landing gear, took off the wheel pants, and removed the little 2 1/4" foam tires, and installed a nice set of 3" Sullivan light weight rubber tires. They fit perfectly in the wheel pants. I removed the little 1/2" tailwheel, and installed a 1" one. It looks like it will have decent grass clearance.
I'll continue with the next post. Dean

Crash Find - Skybolt
 

Here are a few more after I painted the pilot-- Dean

It all looks real good, not bad for a hundred bucks and a little work. Good job

Crash Find - Skybolt
 

I'm finally starting to put the finishing touches on the plane. I got the firewall painted, and checked the alignment of everything for fit. I remounted the motor mount and engine, fit the fuel lines to the tank, and decided to add a quick fueler fitting for fuel, and one for exh port, since everything is pretty well hidden under the cowl. The only thing that I didn't like on the front of the fuse was the large indentation at the bottom, just behind the firewall. I assume that is there in case an electric motor was going to be used, for ventilation. I decided that I would rather like a cleaner looking bottom, and I added a few hard stringers to the area, and made a cover for it. I covered a piece of balsa with Monokote, and added the red and gold trim to that for a nicer finished look. I have to route the 72MHZ antenna thru the fuse, and secure the RX, and battery, and do a system check on everything. I hope to get it to the field for maiden flight. I hope to get pics of flight. Dean

Thats a great deal!

Crash Find - Skybolt
 

Well, today, I pre assembled the wings on to the fuse at home, and checked all the throws on the control surfaces. I centered the lower ailerons, and checked for throws according to the manual, and checked them on dual rate. I had them right on. I installed the top wing, connected the lower aileron pushrods to the upper wing, and only the left upper needed a little trim adjustment. I checked CG according to the manual, and it was right on. The rudder and elevator only needed a little tweaking to have them centered. I turned on the transmitter, and ran it thru a set of cycles, and everything was ready to go.
I went to the field, set everything up, and did a range check, and everything worked perfectly from over 100 paces. The radio I am using is the older Futaba FP7-TFG Gold series radio on 72 MHZ, Ch 56. The radio was completely serviced by Tony Stillman at Radio South, and I had him install a 2500 MA TX battery. The motor is an OS 61FX that I had little time on it, and I had already tuned it on my engine test stand with a 12/6 XOAR prop. One of my friends at our club, Les, is an outstanding pilot, and he is usually the clubs "Test Pilot" for anyone wanting a new plane checked out, test flown, and trimmed out. He throttled it up, and it went down the runway smoothly, and lifted off effortlessly. Took it up to a safe cruising altitude, and only needed a click of down trim on the elevator for a hands off smooth flight. I asked him to put it thru a series of aerobatics and pattern maneuvers, and the 4 point rolls, knife edge, inverted flight, cuban 8's, and knife edge circles were flawless. He went full power, and the vertical performance was unlimited. I asked him for a couple slow passes for pics, and it flies as well slow, as it does fast. I'm very pleased with the outcome, and can't wait to take it out again. I enjoyed this project, and I have a fairly expensive ARF, with minimal investment, and a few hours each evening refurbishing a nice plane. Dean

Nice work.

Thank you all for the compliments. I really started this kind of post to maybe inspire some of the Newbie flyers on a cost effective way of getting a fairly nice, reparable plane for a bargain. I know that many of the newer flyers at our field, and club barely know anything about building from a kit or plans, and the ARF plane is readily available, pretty cost effective, and quick to assemble. I do think as an old timer, and longtime builder that a lot can be learned from building a complete kit, or as many of mine are- "scratch built". I think some are too lazy to try a full build, and some just don't have the time or space to do that. I have seen many at our field start with something way too advanced for them, and get disgusted when they crash one, and don't really know where to start to do a repair.
I hope that some have read this, and maybe learned that it isn't too difficult to make repairs and improvements on a crash find, and can often get a fairly expensive plane for a small fee. I have a huge stash of balsa, and hardwoods, as I assume most builders do too. We builders all have our supply of wood and extra hardware to do these kind of rebuilds. Everything I used on this repair came out of my "Scrapbox".
Thanks again-- Dean :D

Do you happen to know what it came in at for a weight? I'm working on a Skybolt and was worried the 61 was going to be a tad small.

Hi-- This plane with all the repairs came in at 7-1/2 lbs.Now, understand that I added a thicker firewall(3/16 ply), hardwood (Basswood) supports inside the front fuselage, a larger (16oz) fueltank, larger rubber tires, pilot, some extra support pieces. Doesn't seem like much, but those ounces add up quickly. When I started the repair, I weighed all of the parts(minus firewall, & some broken front formers), and the AUW without engine, battery, and servos on;y weighed 5.14 lbs.
You didn't mention whether urs is the GP ARF, or the kit built Sig version. I do have the Sig kit built one, and it is almost 10 lbs with everything installed. The OS 61FX is a real powerhouse, and will almost 3d. I had one of our 3d pilots wring it out, w/ a 12/ 6 XOAR prop, and he told me if I was to install and APC 12/10, or an APC 13/6-7, it would probably hover. I just did pick up those 2 props, and will let him fly it again to see the difference, and if it will 3D. Which .61 motor will u be using ?? Most of the time, I just cruise around the field at 1/4- 1/3 throttle, and it cruises nicely- NO bad habits, and lands beautifully with only a click or 2 of power. I'm not into the 3D type of flying, just general sport flying, and I would like to learn some basic pattern routines with a bipe. Of course, that's just me, so I know u will really enjoy this plane. Let us know how ur progressing, and how u will equip ur plane-- Dean

My Skybolt is a kit built Great Planes. I picked it up 2nd hand and it has a O.S. 61FX in it. I am a fan of OS engines, I just am not sure if it will have enough power for the heavier plane. I haven't gotten it on a scale yet but it feels somewhere in the neighborhood of 7-10 lbs. I have a Goldberg Ultimate with a Saito 1.50 that feels lighter. The skybolt hasn't been flown and was built by a inexperienced builder so I may uncover it and see if there is any places I can shave some weight. It has some other linkage flaws and the aileron hinges were not glued on well at all so those will need to be redone as well.

Hi again- I would think that the OS 61FX will fly ur kit built one easily, as I only had to put about 1/2-3/4 throttle to get mine off the ground. I fly mine with only 1/3 throttle, and it cruises around nicely, and at a nice airspeed to do rolls, loops, knife edge etc. At full power, it is a screamer, and a little too fast for me. I did pick up a 12/10 APC pattern prop that I'm going to install for our 3D Test pilot to try out. I think u should give it a try with the motor u have, and make a judgement call after a maiden flight. Let me put it this way, I have a scale Piper Vagabond, just under 11 lbs, and I have an HB 61PDP motor in it, and is more than enough power to fly it. I think the OS 61FX motor has a little more HP than my HB 61, so I wouldn't rule the 61FX out. I think u will be surprised how potent the FX motor is. If, after a test flight, and u think u would want a little more power, u could move up to the OS75AX, which is really powerful, and has the same case size I think.
If ur going to uncover it, look at the structural integrity of the build befor u decide to do some cutting away for lightness. There might be a few places that can be shaved, but remenber, the Chinese ARF uses a lot more inferior wood and ply than the original American GP kit. Let us know what u find, and try to get an appx weight of just the airframe, then weigh the added parts-- motor w/ muffler, fuel tank, battery, servos etc, and then u will know an appx AUW. If ur under 10 lbs, fly it with the 61FX. Dean

I definitely will. After seeing this thread I moved the Skybolt to the front of my line up for finishing. Unfortunately the flying season is coming to an end here where I am. How do you get your weights? I was thinking a bathroom scale but not sure how sensitive they are. I have a shipping scale at work that is digital I may try.

Hi- Take advantage of any kind of a decent flying day u may get when u get ur plane ready. I'm sure there will be a little Indian Summer coming. I have a postage scale that goes up to 50#, and that's what i use. I don't think a bathroom scale is very accurate. Shipping scale should work fine. I weighed everything separately- each wing- fuse- struts- landing gear before i started the repair work, and again after repairs. Then I weighed all the other add on parts. I just took out my scale, and had the plane all assembled, put it on the scale, and it weighs 7.66 lbs. I do have a 16oz fuel tank in it, so i would think that 16oz of fuel would take it to the 8lb range. So, I do think that even at 8-10 lbs, the 61FX will fly it with plenty of power. It should fly with decent authority, and u will have to judge how much more performance u want out of it, but the 61FX will be an excellent start. Let us know how ur progressing-- Good luck-- Dean