da Rock

What diameter prop do you expect to use?

stingerg64

I want to try a 15/8 vess if there is enough clearance. Was a little concerned about getting out of the wing load envelope and ruining the flight performance.

LMProd

Has any one tried this plane on Floats ?

da Rock

Here is my Skybolt with a 12.75" prop on it. It's got about 2.5" clearance on a vinyl floor. Our field is grass and that prop is no longer clean and pretty. Well, actually, that prop is no longer on the airplane. I'm running a 3blader now to get better performance with a touch better clearance.

Mine weighs 7lb 4oz dry. It's the ARF version that's been out at least 4 years now. The kit version often weighed a couple of pounds or more heavier than that. It's quite agile with the OS61FX I stuck in mine.

When you're wondering about how much weight you might be adding, figure twice the difference between a known engine and the one you're planning to use.

Fact is, I wouldn't worry about the weight as much as I'd worry about the firewall being able to support ANY engine, much less a more powerful one. It's made of two layers of LITEPLY and is basically unsupported it's top 1/4th. OK, it's supported up there..... by a foam fuselage about 3/4" thick sheeted with something like 1/16" balsa.

da Rock

I just looked at the Skybolt down in the shop and.............

That picture was taken with a prop that's actually closer to 12.5" than 12.75". I have a selection of some of my most often used props that have a couple of trimmed versions in the pile. Take that OS61 for example. I got a handful of 13"ers of different makes. And the handful includes duplicates that're simply trimmed a bit. Sometimes when trying different props on a plane, one prop will seem to be just a bit too slow. If you got the same one that's a half inch shorter in your bag, you can see what it'd do with that little extra rpm you wish it had.

A more important detail about the clearance issue with the ARF Skybolt is the gear. It isn't exactly stiff and it relaxes a bit from use. Mine needs to be pulled back down a bit almost every other outing. I quit doing touch and goes with that plane because of that gear. I've planned to add a stiffiner wire for awhile now but haven't gotten around to it. I even bought a replacement gear to do the work on. It was as "stiff" as the original.

I've not looked into aftermarket for the sucker, but it'd be sensible to consider that if you plan on a larger engine or just a longer prop. If you discover one, how about posting it here. I'm sure I'm not the only Skybolter who'd be glad to find out about that.

nikon44

I have a older O.S. 61 SF would it fly it nicely?

summerwind

Stinger64,

i'm flying mine with a YS 110-s and a 15x8 APC..............goes straight up and out of sight at a little under half throttle.

haven't snagged a prop yet even with a couple bouncy landings

da Rock

The original often hefted near 10 pounds dry. Very few people back then flew much larger engines. I really don't remember ever seeing a kit Skybolt with anything other than a 60 on it. And it flew so good it became a classic. So the ARF is at least 2 pounds lighter. Yeah, I'd say your 61 would do very, very well.

No matter what you put up front, I would suggest that if you have the skills, slap another layer on the firewall. Any thickness of AeroPly would be good. Any ply other than LitePly is made of decent wood and each ply is strong. 1/16" would be just fine.

summerwind

Ditto on what Rock says about the firewall.................thing is, the lightness of the ARF is due to many areas having been lightened by using not so strong materials...strong enough for the suggested engines, but the firewall is not near strong enough for the higher powered engines.

i saw Rock's pictures of his firewall when his broke, but didn't give much concern until my first SS came in at mid power on a spiral downward angle hitting the left wingtip first then the engin hit at probably a 30 degree angle...(radio failure was the cause).......the firewall literally disentegrated which was probably a good thing as it saved the motor..........but with anything more powerful than the OS91 SurpassII i would be afraid to stand in front of it.

the lightweight of this ARF and the 61SF will be a good combo........propped right and you'll have a blast.

g_mkoch

I have mine with an OS 110 and it has all the power it needs, unlimited vertical and great fuel consumption. I'm running a Zinger Pro 15 X 6 with no clerance problems.

Jeff Spicoli

Can anyone give me the approximate internal clearance on the cowl? I'm thinking about installing a Saito 90ts twin which was intended for another plane.

Thanks
Angelo

stingerg64

Summerwind /daRock thanks for all the info on this plane. Really wasn't looking to put a bigblock in a smallblock hole but the smallest gas motor that I have is this evo 26GT2. After viewing the construction of this plane I could make it work but from all indications would turn it into 10 to 11 lb. turd with alot of speed. Does anyone make a 120 size ARF in a Super Skybolt? Thanks again for everyones input. Stingerg64

Meschmidt

My Feedback: (15)

Has any one tried this plane on Floats ?
[/quote]
I'm in the process of putting mine on floats now. Got them in the right place and it balances and sits in the water very well. All I need to do is some waterproofing, paint the floats, hook up the rudder and go fly. Will post flight results and pictures soon. Looks like it's gonna be a very sharp lookin' float plane! Paul

camgab

Hi

What is the correct code of red´s monokote on the fuselage?
The construction manual says: Red metalist (TOPQ0405), but I think that is incorrect.
Sorry for my english
Camgab

MormonMike

My Feedback: (2)

Paul, That's quite impressive and novel. I never thought to try floats but it sure looks great !. I still keep a check on this thread now and then. MM

g_mkoch

g_mkoch

I'm in the process of putting mine on floats now. Got them in the right place and it balances and sits in the water very well. All I need to do is some waterproofing, paint the floats, hook up the rudder and go fly. Will post flight results and pictures soon. Looks like it's gonna be a very sharp lookin' float plane! Paul
[/quote]

What field do you fly at?

orangepeal

My Feedback: (2)

I'll be getting one this year for the holidays. I plan to use a 91 4 stroke (probably a Magnum) which will be my first 4 stroke. When using a motor within the suggested parameters from Great Planes, do you guys still think it necessary to reinforce the firewall? Or is this something that folks have been doing so that more powerful engines could be used? I typically go over the interior of an ARF with CA, and use epoxy for the abused areas like the firewall (or motor box in an EPplane) and the landing gear. You think this will be sufficient for this plane when using the suggested engine size? Thanks!

opjose

I used a four stroke .91 sized engine in mine and I did NOT re-inforce the firewall.

But after seeing the pictures which I believe Da Rock put up, I immediately wished I did.

Doing this before you put the engine in is relatively simple.

The problem with the Skybolt is that the firewall is held on top at only a few points and the firewall is fairly thin.

I believe Da Rock's solution was to put another laminating sheet of hardwood over the existing firewall, and add additional re-inforcement behind the existing firewall.

Doing so before you mount the engine would be almost trivial.

da Rock

Jeez, are you kidding? The pictures of that firewall must be far enough back that you missed them.

It is basically not very strong. It's made of two layers of light ply, which really isn't a good choice for firewalls. Lite ply doesn't stand compression, like from the bolts that cinch down the T-nuts that hold the motor mount on. And lite ply isn't really plywood. It's really a single ply of softwood with veneers one either side. And that ain't all.

That firewall isn't supported around the upper 1/3 worth spit. Its perimeter glues to the balsa fuselage skin that's about 1/16" that takes its shape from foam. They had a chance to support it horizontally in that upper area, but they "lightened" the center part of the bulkhead up there. Amazing design, absolutely amazing.

Will yours stand up? Mine has since rebuilding. Mine failed because of what I've recounted. Many, many have stood up, but why chance it.

My advice is to duplicate the face with some real plywood and layer that on. In my case, the plug that the motor mount cleanly punched out was replaced before the new layer was added. I also cut some round pieces to go on the inside to support the T-nuts. They aren't really necessary if you'll soak the existing holes with CA to insure whatever quality your lite ply is, it'll be strong enough to stand the compression. Lite ply does strengthen up nicely with CA. I wish I'd known to do that, but this was the first firewall I've had that failed from poor wood.

One layer of airply and CA in the holes would be excellent insurance. As the picture shows, it's not a bad thing to do. It is a bad use of liteply however and they should never have left the upper area unsupported.

da Rock

BTW, see the cowling in the background of the picture? That is the original. A couple of minor cracks was all that happened.

The firewall was failing in use. What caused the rest of the damage was my flying screwup when I "landed" it at the bottom of a flat spin. When it was obvious I wasn't going to get her out of the flatspin, I took the throttle to idle and she hit in the soybeans. As we walked up, everyone commented how lucky I was because there obviously wasn't any damage. Heck, the gear wasn't even bent, and it's not exactly strong metal. I couldn't believe there was absolutely no damage and sho' nuff, it wasn't true. When I picked it up I noticed the "spinner was loose". On inspection it was sho' nuff more than the spinner.

That cowling is flying today, as is everything that came in the box. Good flying plane.

orangepeal

My Feedback: (2)

Ok, I'm sold. I will definitely reinforce it just to be safe. Thanks for the info and pic.

marcoferretti

My Superskybolt has about 90-100 flights, it's my everyday flyer!
It's powered by an OS91 4 stroke. Performs beautifully and during my monthly inspections I see no failures in the engine compartment, no signs of firewall weakness. My firewall holds the engine, the smoke pump and battery. These items are in the engine compartment because of the nose-weight needed to balance.





If you feel that firewall needs to be reinfornced, just do it, but the Skybolt is strong enough to hold a .91 engine for hundreds of flights.
Enjoy this bipe!
Marco

da Rock

Marco, your picture shows a reinforced firewall. Those vertical pieces do quite a bit to resist vibration and stiffen the upper area that's almost unsupported. Both the vertical plate and the square stick help out your liteply. And you were lucky the liteply in your firewall was not flawed. Not hugely lucky, but a bit lucky, because most liteply isn't going to be flawed. However, some will be.

The irony with liteply is the almost worthless (for strengthening) veneers hide the one ply of real wood so it can't be inspected during manufacturing, and we can't inspect it after purchase. Since the soft, light wood used is just wood, it's going to have checks and flaws more often than denser, stronger wood, and the flaws are going to be hidden. The veneers are simply going to hide voids and punk areas with no real support. It's a crap shoot if your liteply firewall is going to be made of decent wood or not. It's your money to gamble. Hey, lots of guys have not done a thing and their Skybolts are still flying. It's obvious that more often than not, firewalls are standing up, at least for a season or so. It's also obvious there is a gamble on each and every one.

Liteply is a really ignorant choice for firewalls.

marcoferretti

Hi Rock!
The vertical piece and the vertical plate are things I added to place the smoke-pump and battery the most forward to get the correct CG without adding lead. Let me call it "useful weight".
When mounting the kit, I did reinforce all glue joints in the firewall area. I don't know if this was helpful or not.
Next, I brushed finishing-resin on the firewall before installing engine mounts. Even the best ARF manufacturer will say its models are perfectly fuelproofed, it is not so. Did the resin help to make the liteply firewall more robust? Could be. My firewall is actually holding the engine, the smokepump and battery weight, all these items plus mounting plate etc.. are worth about 2.4lb. The acceleration of flight/aerobatic maneuvres applied to such weight will result in an impressive force applied to the firewall itself. So far I had no issues, hope I'll never have any...

BTW, I agree a firewall should not be made of liteply. True this ARF is "the" lighter version of the kit-skybolt, but there is no reason in making the front area so light if some ballast is to be added in any case to get a correct CG. Oh yes, I got it: it's just a matter of cost....