oneqwk96gt,

What are you using to break in your os91? I also have purchased the os FS91, but its my first 4 stroker and I want to make sure I dont damage the engine. I've been advised by the hobby store to use 20/20 100% synthetic fuel. Any comment?

i have always used morgan omega 15%. this is technically 2 stroke fuel (castor/synthetic blend) i used this fuel for everything with the exception of my heli. i am about to buy a gallon of omega 4 cycle mix, still castor syn blend but i believe it has more oil. this is the only fuel my LHS has right now and i figured the little extra oil couldnt hurt especially on break in. just read the running-in procedure for your o.s. 91, my engine is turning a 14-7 Graupner 2 blade at 8450rpm at optimum setting on the first tank of fuel! this engine is really sweet. i then turned the high speed needle 3/4 - 1 turn back to 6900 rpm for most of the first 2 tank fulls. i like using a little castor all the time just for the peace of mind but if you set your engine properly then synthetic should be fine. its just that there is a lot more parts in a four stroke and the castor helps. just my .02

Well ALWAYS go by the manufacturer's suggestions for break in. That trumps the LHS's recommendations.

That said, some manufacturers ( such as Magnum ) recommend breaking in the engine with a Castor based fuel initially, then moving to a synthetic after the initial breakin period.

Castor produces a varnish like coating that turns back into a slippery substance when it reaches a high temperature, to it acts to protect the engine components from heat and wear during that important initial period.

oneqwk96gt,

i see you found one way to use the CG machine........i was tempted to do the same thing, and then it dawned on me, what was needed and worked was to simply shim the front of the CG Machine up with a piece of 3/4" stock pine or any other material that is this thickness.....it then moves the rods back far enough so the landing gear doesn't hit, and in this way you don't have to hold anything in your hands, and the rods remain mounted in the machine.
mine balanced right on the nose, but i too have since moved the CG back 1/2".................whole different airplane now.

hey yall. i just got back from the field. skybolt flys great, it felt like i had ben flying it for a whole season already. beautiful plane. she flys wayyy nose heavy and that is with the cg at 4.75" thinking of adding a pilot to it and see where the cg is after that. for anyone thinking of getting this plane, you will love it. i have a os 91 four stroke and a graupner 14-7. and she flys awesome. plenty of power as it is still very rich.

glad it went well...............i'm flying mine with a Top Flite PP 14x6, and it pulls like crazy, but i keep hearing great things about the Graupner props.......i'll have to give that one a try.
also PM'ed you

I just finished assembling mine. It came out perfectly balanced at the 4-5/8" balance point. However, it still needs to be balanced laterally. The right wings are heavier than the left.

I tried to run the antenna wire down the tube provided before installing the servos, but still couldn't do it. I came up with using a length of push rod I have for park fliers. I run that down the tube from the rear, then glued a sewing thread to that and got the thread in the tube, then glued the thread to the antenna and then pulled it through.

My only other problem was my big fingers and all that tiny hardware.

vrhoward1122,
I found the cg on the skybolt to be very conservative. i have ordered the pilot
for the skybolt from great planes( 1/5 scale) it weighs 1.6 oz. i found that if i put the pilot in the canopy at the rear then this will bring the balance back the rearward position of 5" i think then it will fly a lot better. mine took a bit of up trim and when i rolled the skybolt inverted and went to a 45 deg upline it pulled right out. this tells me she is too nose heavy at 4.75" i will post my results if i can get out to the field this weekend and try it. the pilot should be here this week. that is just what i found and i know that many others noticed that about the balance on this forum also. oh yeah, i agree with the antenna wire tube, it took me over a hour to get that sucker down there. by far the hardest part of assembly.

I am considering buying this ARF, and have wondered how well the covering and it's complex trim scheme are holding up in the field. I would appreciate some input from you folks who have had theirs for awhile. It's a beautiful plane but I can see the trim coming loose after a few cleanings. I also would like to hear from anyone that flys the airplane with a 2 stroke .61 or equivilent four stroke. I am considering using a Saito FA-80 that I have lying about. It is a strong running engine and I'm not going to load the plane up with a smoke system. The Saito will turn a 11X8 APC 11,000 RPM. Thanks.

I have been flying my Skybolt for over a year and the covering is holding up well with the trim staying put. You have to be careful though with the checkerboard covering on the bottom of the wings. It seems to be fragile with regard to applying heat. When smoothing out wrinkles, use a light heat setting. Mine is flying with an OS 91 Surpass II and 14x7 Graupner prop and it's all the power it needs.

FYI, I have a Saito FA-100T in a SIG Waco SRE that weighs 9.5 lbs. and it is a prefect match for this plane. Half throttle makes for a very scale like preformance and full throttle pulls the plane vertical very well. The Skybolt at about 8.0 to 8.25 lbs. should give the performance that you are looking for and the sound is great. Hope this post isn't too late.

Thanks for your input. Guess it's time to pull the trigger.

I'm just finishing up the ARF and getting ready to fly in the next week or so...

The covering *(with the exception of the checkerboard) is all Monokote as far as I can tell and should hold up as such. I have an OS FS .91 with a top flite 15x6 powerpoint prop that I am going to be using. Any feedback from the group with respect to a new OS FS .91 and the 15x6 on this airframe?

Also,

I'd like to leave the canopy off and leave it open cockpit - I just like the look and have one of my daughter's Barbie's flying (Patty Wags'). Will that throw off the flying characteristics?

WSHall

My only gripe has been that there is no place to put wing tip skid guards on.

My wing tips have a bit of asphalt rash as a result.

Otherwise my Skybolt is going on 2 years of flying now.

I ahve been flying mine since last summer and I love it so much I hace flown it just about everyday. I am also using the O.S. 91 four stroke and it works out perfect for my style of flying. I am also using the smoke system with out any problems. My covering still looks as the day i bought it.

I got my ARF in Fall of 2006. It's covering had some stubborn wrinkles where the trim is layered. It took high heat with an iron to get 'em out and they came back about 1/2 size. Took 'em out and a couple have come back since. The trim definitely did not come loose, but the wrinkles are as stubborn as a 4 year old.

As for "all the covering" being Monokote. Not on mine. The orange/white checkerboard is definitely not Monokote. It is not as strong for sure. I've had to patch mine a couple of times. Nope, not Monokote.

I've run an OS61FX since day one. It's got a number of favorite props. 13x6 two blades seem to work about the same no matter what brand. Right now I'm running a MA12x6 3-blade because it seems to be the best match for the engine/airplane. And it looks kewl, too.

wshall,
I also have a os 91 fs. I am using a Graupner 14-7 prop per Minnflyer's recomendation. I have 5 flights on my skybolt now and i am starting to get her setup for my style. (i would have alot more stick time on this beauty if the weather wasnt so terible here in michigan) Moving the balance back to 5" by installing a pilot. (flew too nose heavy for my taste) Mine is built exactly per instructions and the graupner 14-7/os 91 fs pulls it very well. It turns 8400 rpm at a rich setting, (1st 2 tanks) You will have to pull the power back so the vertical uplines dont get to high on yah with this setup. (i lose sight of it otherwise) I wouldnt call it "truely unlimited vetical" but very close.

as for the covering i agree with darock about the "stubborn as a 4 year old" wrinkles. My wings were great, my fuse was ok, i should have used a heat gun on the fuse first then went over it with a iron. I think if a heat gun is used carefully then you have exellent results. Its not that the covering job is bad its just that there is so much trim layered on. If you used a iron first then is kinda shriks, kinda irons on some wrinkles because the covering adheres to the wood before it can shrink a lot. (this is what hapened with my fuse however now it looks great.) after 2 trips to the field and 5 flights the covering looks good as new.

Thanks to all for your imput. I have one on order as we speak and your comments have been very helpful in making the decision. Da rock, if that is a recent photo, then I have little to worry about with the covering. I'm still hoping my chosen engine (Saito FA-80) is going to give me as good performance as this plane deserves. At 7.5 lbs. max weight it should, but it still looks like most of you are using stronger engines so I have some doubts.

The original was a kit that built heavier than today's ARF by way more than a pound. And most people back then flew them with 60s. They flew so good the design is still around. So don't let the doubts bother you too much.
Your plane will be more than a pound lighter and your engine will be equal in power. It'll fly better than the one that started the legend.

The pictures with the 2bladed prop were taken back in 06. It's been flying since Fall with the 3blade, so if the picture shows a 3blade, it's how it looks now. Monokote and Ultracote keep their looks for years.

The weather finally co-operated this Sunday and I got to fly this plane. I think my other planes are going to get neglected I like it so much. I got it on the runway and advanced the throttle slowly. By the time I reached half throttle, it was off the ground. I only had to ginve two clicks of up elevator trim to get it to fly straight and level. I did some bsic aerobatics to test the plane out and it tracks like it's on rails. Slow rolls are beautiful with this plane. Did most of my flying at half throttle with a couple of times I went to full throttle. Landing was extremely easy. Wasn't a floater like my other planes. I was ready to have to go around a few times to get it set down, but I set it up for approach and went to idle on the throttle, it came down at a steep angle, I flared it and it landed nice and smooth, no bounces. One of the few perfect three point landings I have made and it was the maisen flight.

Just outstanding. Handled well in the 5mph cross wind we had today also.

I am using a Magnum .91 four stroke and it takes off at half throttle. Pleanty of power.

Hey Rock. You appear to the be the guy to turn to with questions about Skybolts, so I'll ask... He you flown a SB without a cannopy? I want to fly and open cockpit plane but an a bit concerned about what the open cockpit will do to the aerodnmanic properties.

Thoughts?

WSH

WSH,

Refer to page 4, post #79 and page 8, post 191, in this thread. Damifino has done a marvelous job on his Skybash. (his words.) I imagine he would be able to tell us how his flies with the open cockpit.

BTW I am hard at work on mine. I build so darn slow. [] But it is nearing the end. Tonight I did the linkage for the ailerons on one side. I did it the DaRock way. DaRock, your picture, back at the Ultimate thread, was a great resource. I basically copied you verbatim.

This is my first bipe. I am astounded at how heavy they are. Mine is 7lb 13 oz. That is right in line, but it is such a brick to pick up! I guess you have to look at it that there is LOTS of wing area.

WSH,
Bipes fly much the same with or without a canopy. There is all that cabane junk ahead of the glass that has already thrown a ton of drag at the airframe and mixed the airflow into a froth. So having a full canopy or not can't change much percentage wise. I'm certain that the open cockpit look will be kewl. I'm surprised more people haven't chosen it. The airframe looks very much like that era.

Vinnie6,
Kewl. I recently let a guy fly mine who has one of his own. He wanted to see if my layout flew better. Truth is, he sorta had a chip on his shoulder to prove it wasn't worth it. So he lands and says he sees no difference. So he wants me to fly his, and while trying to sell me on that idea, mentions "the only thing you have to look out for is....." Interesting that he thought I would need a warning...... After all, mine flew "no different", right?

Don't worry about the weight. The kit version has been around forever and builds a lot heavier. And has flown so good since day one that they ARF'ed it. This ARF really does benefit from the lighter weight. My 60 pulls it significantly better than the kit ones I've seen fly and they fly excellently.

Thanks DARock / Vinnie6 for all your advise. We've all got a lot invested in these kits, and customization is always fun. This forum is a great place to get advise from the true experts.

I'll post some pics and let you know how it goes.

WSHall

Da Rock,
Do you have a different way of setting up the Aileron linkage? Do ypu have a link?

Thanks