You've probably got the most 'Bolt experience in this thread, so I'll ask you.

I plan to get one, and am hoping that my Laser 150 will fit in there. It should, as it was a perfect match for the Goldberg Ultimate, but… that puppy swings a 16" prop.

Am I going to have ground clearance problems with the stock LG?

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Well, okay… ANYONE here still flying this model?

Looks like my Laser is not going to fit, especially after I add a supporting firewall. New engine choices are sparse, for sure. I'm leaning toward a Saito, probably the 1.25. Again, I'm concerned about prop clearance.

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I'm still flying my Skybolt nearly every weekend. Mine, powered by an OS 91 S2, has more than enough power for anything I want to do. My question is, why would you want to take a 7 lb airplane and turn it into a 10 lb airplane? Mine, swinging an APC 13.5X9, has roughly 2" of ground clearance. A Saito 1.00 would be about as large an engine as I would recommend.

Oh, one more thing. With the OS 91 and a 6v battery mounted up front under the fuel tank required no added weight to balance. AUW is around 7.5 lbs. It flys great and lands like a Senior.

Well.........ok. Maybe not a Senior but it is my most agile bi-plane and landings are a dream.

I don't. Where do you get those three pounds from? The larger engines I am discussing are, at most, a half-pound heavier than an OS 91 Surpass (which I have, but in another model) and, I presume, a Saito 1.00.

But you're right, the 15"-16" props those engines require would simply not work with the stock LG. Which is what I suspected. Your information confirmed it; thanks.

Regarding the firewall… did you reinforce yours by adding a second thickness of real plywood, as detailed way back in this thread? I have no doubt that some additional fuel proofing will be needed, and perhaps some tri-stock here and there. But slapping on another firewall over the existing one is pretty… severe. Necessary, you think? Or not?

Off to check out the Saito 1.00...
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Still flying mine with an OS 95V, lots of great compliments at the field and still looks and flies as nice as it did when new

The 10 lbs was just a number off the top of my head, my point was that you would be making a good air frame heavier. That 1/2 lb would have to be counter balanced some how.
As for my firewall, I replaced it after about my 3rd or 4th flight when I tested the stall speed at 3 ft off the ground. It popped out clean with very minor damage to the fuselage. I replaced it with 1/4 aircraft ply at that time. BTW, I believe the Saito 1.00 is lighter than the OS 91 and has slightly more hp. My 7.5 lb Ultra Sport with a Saito 1.00 w/13.5X9 prop has enough power to hover, though not enough tail to hold it for long.

GOOD HEAVENS !!!!! It's been nine and a half years and this thread is still going !!!!!! I've been away a long time and never checked in on RCU. [ but that doesn't mean I haven't been flying ] I still have my first Skybolt along with a kit-built one and they are the smoothest flying planes ever. Matter of fact, I call them the " Cadilacs ". Both with OS 91, Three-blade MA's. I've never broken a prop on them in all this time plus not one scuff on the wheel pants on either of them...... Not one ! The kit is one pound heavier than the ARF but no difference in performance at 4500 feet elevation. I was really looking to find out why JR stopped making their 1500 mh NI-MH TX batteries when I stumbled across this thread but sofar, no luck. Seeya guys around, MM

Just remember guy's, 3% power loss per 1000 ASL**....sooo....4500 ft. altitude equals a 13.5% Power Loss, very simple. Typical Saito 1.25 minus 13.5% equals a Saito 1.08...just sayin'...


**Normally Aspirated Internal Combustion Chamber Engines. Externally Aspirated Engines such as Turbocharged and or Supercharged engines, this rule does not apply.

I had my kit built bolt on a DLE 20 and a pumped 120 and both were a blast. The 20 cc was better in my opinion.

Since they are BOTH 20cc, I assume you prefer the DLE 20cc over the OS Pumped 20cc....Just Sayin'....

For some reason, the DLE just pulled it WAY harder. Maybe the OS is getting old. LOL.

Looks like a Saito 1.00 is the optimum choice if I have to buy a new engine. My kit will be here first of next week; I'll verify that the Laser 1.50 is a no-go; if so, then I'll get a Saito enroute.

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Has anyone tried stuffing a DLE 20 RA in the bolt yet I'm thinking about it just not sure if it will work any thoughts

been there, done that. All i can say is you wont be dissapointed. You will, however, have to cut your cowl to pieces.

have you any photos of the one you did

Here you go. Man, that was a fun little bipe.

Thanks for your photos stevegauth30 it looks like yours was a kit build I'm looking to put a DLE 20 RA in the ARF and was wondering if anyone has done it or if it will even work

I installed a side exhaust DLE 20 in mine and it was no problem. I have not finished it yet, but will this winter.
Gordon

is there that much of a difference in the motor box and cowl of the ARF? I would think you should be fine

I'm not sure on the later ARF but reading through the forum it seems that the early ARF may have had a weak firewall and I'm not sure if they addressed that issue in the later runs

They didn't. I just opened my recently-purchased kit and had a look; two 3mm pieces of light ply laminated together. It "interlocks" into the fuselage sides, and has a couple of small pieces of tri-stock, but you can pretty much forget about beefing it up further from the back side; too much of a stretch and too much structure in the way.

The box says a .70 four stroke is acceptable. I find that a bit… optimistic, at the very least. No joy on the 1.20 Surpass I was promised, so I'm back to deciding what engine to get. I want plenty of power, but I don't want to bust that flimsy firewall loose with too much power.

This is annoying...

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LSP 972- The most recent GP Skybolt ARF is pretty much the same as the earlier ones, with their selection of wood that thay use. I bought mine used/ wrecked at a swap meet, and only the firewall, and front formers were damaged. The previous owner that I bought it from has an OS 91 4 Stroke in it, and on his 2nd flight, he ground looped it, and the OS 91 went straight back and took out the firewall and F1-F4.
I did a refurbish of it, and have an article in the "Crash/Rebuild" forums here on RCU. If u go to that forum- go to page 4, and look at my article "GP Skybolt crash find" near the bottom of P4, and u will see how I rebuilt the front end, and added a lot more structural integrity to the front airframe. When u go to fly urs, make sure u let ur groundspeed get hi enough, and it will lift off effortlessly. You also may want to cut, and add an additional 1/8" ply firewall to the existing one for added support. I'm flying mine with an OS 61SF long stroke, and it will do anything I want it to. Here are a couple pics, but u can check out my article if u like. Let us know how u will progress with ur assembly, and maiden flight- Best of Luck-- Dean

Many thanks for that, Dean. It looks to be the simplest solution to the problem.

I let a 1.08 FSR get away from me a few years back… sure wish I still had it for this airplane.

It will be a while before I get around to starting this one, so I've got time to select an engine. I'm just real hesitant to buy used these days...

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