Hello

While I am perfectly aware of the Jett 90 as a performance enabler (I saw the vid), which other engine would fit ? Would an OS91FX / Jett muffler do the job too ? Has anyone ever flown this a/c with another engine setup than the Jett 90 ?

Thx

Yes the OS91-FX will fit and with the Jett Stream will have decent performance but not up to par with the Jett 90LX

kc

OK thank you for your input [8D]

Any other suggestion ?

Yeah, get two Jett 90LX's when you order, you'll like the first one so much that the next time you are in need of one you won't have to go through the wait.

kc

kc, unfortunately, I cannot afford a Jett90 right now [&o]... They are listed $400... Maybe in a distant future

However, I have a somewhat unusual idea. Why not get two .50/55 sized engines (maybe some different engines) and install them with a push / pull configuration ? Two webra .50 for example ?
The main problem would be the prop strikes at the back, thus requiring higher mains and a three bladed prop at the back.
What so you think about the power of this setup ? What would be the two-engine equivalent of a Jett 90LX ? In terms of thrust ...
Having a smaller engine in the nose has another advantage (in addition to the lower price), it can be hidden more easily than this big 90 beast... And I can use engines that I already have... Running a full length pipe at the back (inside the fuselage) could be easily done for increased power, as there must be lots of room there. Anyone can confirm ?
What do you think of that twin engine setup ?

i think you'd be wasting your time doing it and you'd find it wouldn't be at all fast. speed = $$$ no way to avoid that.

kc

Hey, Strykaas

I have an F-4 build thread over at Scratchbuilding. I had a Tower 75 on it that pooped out, so I stuck a Magnum 91 on it. If anything, the Phantom is bigger and heavier than the AK Su-27. I'll try to let you know how it flys. I have a Magnum 91 4S and it has be my best engine ever.

Gotta wait until I can afford brakes before I try it. 350' paved runway with a nasty overrun.

Hi Bob ! How are you ? I remember your arrow...

Nice to hear you still have the faith in building . OK I'm waiting for your input. I will post this question in another forum section, as I think that the "'Jet" forum is merely read by turbine guys, and most of them are not keen to be helping frogs out !

all the jet guys/gals are more then willing to answer any question they have experience with. you'll find most of them have gotten away from glow engine planes. the AK is an Extreme Speed Prop Plane and there is a forum just for those type questions but you'll find Most everyone there is going to suggest a Jett as well.

kc

kc
This is indeed where I have posted it a second time. Thx

Strykaas:

I'm hanging in there. Things kind of exciting where you live, eh? I don't believe 99% of what I see in the French media or what French politicos say. I remember my trip there, and the fact that EVERYONE was nice to me and many people thanked me (who had nothing to do with it) for America's participation in the liberation.

I'll always be a builder- it's the only thing that keeps me from going insane during the long, northern Michigan winters.

I've joined a club about 85 miles from here that has a paved runway, so perhaps my fast airplanes will have a better chance of surviving.

Regards.

Bob,

thanks for the kind comments about the frenchies...
Wow 85 miles is not close, but yeah paved runways are a better option.
You F4 is a good flyer, I have alreaady seen one, and it was great.
Good luck !

Strykaas:

Was the F-4 you saw the Pavel Bosak design?

If so, I'd be really interested in your memories about the way it flew on approach and landing.

Bob,
I can't really remember which design it was. Is yours built per plans ?

Strykaas:

Pavel Bosak designed it as a "trainer/pattern ship", and the build article was in the April, 1990 edition of Radio Control Model World. I got the plans & canopy through traplethouse.com, which owns RCMW. It's notable among PITN F-4 designs in that it has no fake "air intakes", and so is very slippery looking. Pavel said his would do 120mph in level flight (clean- gear up)with a piped Rossi 60. If my Magnum .91 swinging a 12x8 can get up close to 16,000 rpm, then this one will do about the same.

The one I saw was definitely not this one, Bob, I remember now, it was an ARF, maybe vmar ... Pavel's looks like it has a very big and thick wing, which I believe is an indication as to its flying characteristics.

USE THE OS91 2S ON THE AK! JUST DO IT, YOU WILL LIKE IT!

I just installed an 0S 91FX on my Phantom, which replaced the Magnum, which replaced the Tower.

If it runs anything like what I've heard, I'll be using one on my AK when I finally get around to building it.

The OS91 will fly the AK like a rocket, it will fly the F-4 like a rocket with a bit of a headache. The TF F-4 says 60, but no way. The 91 fits nicely and really flies it with authority. Best choice really. Oh, I glassed both the F-4's and SU's. The SU really needs it due to the really soft light balsa and ply. 3/4oz cloth and resin from the hardware store, no reason to buy the same stuff elswhere and pay three times the price. Have fun!

teebox:

Which F-4 is the "TF"? (Mine is built from Pavel Bosak's plans, circa 1990) He used a piped Rossi 60. I thought a larger, less exotic engine would deliver the same performance with less stress.

BTW, I started breaking in the OS 91FX today, and it is a real sweetheart. Started on the first hit and never missed a beat, unlike both the Tower and the Magnum, which were cranky about starting and couldn't handle the jumper tank fuel system. (The OS will go vertical with no loss of rpm. The Tower and the Magnum couldn't do that.)

The Top Flight F-4 came as a kit, quite a plane to build, large, beautiful though. Out of production. I have a couple, some pop up on the net once in a while. You can't go wrong with the OS. I run several tanks through them, two rather rich, a couple a bit lean. You're correct, easy to start and reliable. Have fun!