FUN SCALE MOSQUITO - MY FIRST TWIN
09-25-2005, 03:40 AM
#1
FUN SCALE MOSQUITO - MY FIRST TWIN
If anyone is interested - I thought I'd post a few pics of my first twin.
It's scratchbuilt, 76" span, and uses two OS 40 fourstrokes (old, non-surpass).
Model in the pics is about 12 years old, pics are from a few days ago, engines are 18+ years old. Not powerful, but work wonderful.
Built as an introduction for me to twin flying.
I've had an engine quit three times, but landed safely. Reason - the needle valve extension on one engine was working as a vibration amplifier and closing during flight. Once I finally identified the problem, it never happened again.
It's scratchbuilt, 76" span, and uses two OS 40 fourstrokes (old, non-surpass).
Model in the pics is about 12 years old, pics are from a few days ago, engines are 18+ years old. Not powerful, but work wonderful.
Built as an introduction for me to twin flying.
I've had an engine quit three times, but landed safely. Reason - the needle valve extension on one engine was working as a vibration amplifier and closing during flight. Once I finally identified the problem, it never happened again.
09-25-2005, 04:50 AM
#2
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RE: FUN SCALE MOSQUITO - MY FIRST TWIN
Hey EF,
I'm currently building a CMPro 73" Mosquito and I am putting Magnum 52FS on board (kit recommends 32FS or 30 2C). I'm a warbird enthusiast so I'm keen to get any hints on twin flight. I've curently got a 63" Spitfire, a 65.5" Corsair that fly beautifully and I'm hoping my MOssie lives up to my flying skills. I'm also looking at building a 92" beaufighter as my long term project.
Dave
I'm currently building a CMPro 73" Mosquito and I am putting Magnum 52FS on board (kit recommends 32FS or 30 2C). I'm a warbird enthusiast so I'm keen to get any hints on twin flight. I've curently got a 63" Spitfire, a 65.5" Corsair that fly beautifully and I'm hoping my MOssie lives up to my flying skills. I'm also looking at building a 92" beaufighter as my long term project.
Dave
.
09-29-2005, 09:54 AM
#5
RE: FUN SCALE MOSQUITO - MY FIRST TWIN
Hi Dave
A few tips/hints from my experience with my Mossie:
The left engine has no side thrust, the right engine has 2 deg right thrust (it's per the plan)
Engine selection - use enough power to fly it nicely but not too much - if an engine quits on you, you had better have "enough" power to maintain altitude but no more. If you have more - you will get a violent snap/spin entry, with reduced chances of recovery. When I lost an engine, I could maintain altitude on 60-70% power of the remaining one, but the yaw was not at all violent even though the engines are not very close to the fuselage.
On takeoff, your best insurance is airspeed. Not altitude. Aispeed is "money in your pocket" while altitude is "money in the bank". There is not always time to get to the bank. So, a long takeoff roll, gentle liftoff and shallow climb. Once you are at altitude and after completing your turn away from the takeoff direction, you are OK.
I let both engines warm up on the ground about a minute before takeoff, and just before takeoff I run the engines to clear them and make sure there will be no sagging during the takeoff tun.
Landing - plan your approach well and try to avoid a go-around. A go-around is a chance for an engine to quit. I make a large circuit and a very long final approach. It not only looks great, it allows you to abort long before you are low, slow, and on low throttle.
I don't use a tacho. I don't think it's necessary. I tuned each engine alone "by ear" and richened the right engine a "click" or two. It behaves very straight. A "single" by the way is not so "symmetric" either, is it?
Good luck and let us know how you are progressing!
A few tips/hints from my experience with my Mossie:
The left engine has no side thrust, the right engine has 2 deg right thrust (it's per the plan)
Engine selection - use enough power to fly it nicely but not too much - if an engine quits on you, you had better have "enough" power to maintain altitude but no more. If you have more - you will get a violent snap/spin entry, with reduced chances of recovery. When I lost an engine, I could maintain altitude on 60-70% power of the remaining one, but the yaw was not at all violent even though the engines are not very close to the fuselage.
On takeoff, your best insurance is airspeed. Not altitude. Aispeed is "money in your pocket" while altitude is "money in the bank". There is not always time to get to the bank. So, a long takeoff roll, gentle liftoff and shallow climb. Once you are at altitude and after completing your turn away from the takeoff direction, you are OK.
I let both engines warm up on the ground about a minute before takeoff, and just before takeoff I run the engines to clear them and make sure there will be no sagging during the takeoff tun.
Landing - plan your approach well and try to avoid a go-around. A go-around is a chance for an engine to quit. I make a large circuit and a very long final approach. It not only looks great, it allows you to abort long before you are low, slow, and on low throttle.
I don't use a tacho. I don't think it's necessary. I tuned each engine alone "by ear" and richened the right engine a "click" or two. It behaves very straight. A "single" by the way is not so "symmetric" either, is it?
Good luck and let us know how you are progressing!
09-29-2005, 09:48 PM
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RE: FUN SCALE MOSQUITO - MY FIRST TWIN
Hi DVM 100. we have a CMP mosquito with Twin OS 52's flying out here in W. Malaysia. The power appeared quite adequate (esp given that with out 90% humidity and 110deg heat) the 52 will run more like a 45!! [
]. BUT the mosquito was really heavy and very very dragging. the flier a fairly experienced warbird RCs had quite a problem landing it as it had to be landed "hot".
Just my 2 cents
kind regard..
]. BUT the mosquito was really heavy and very very dragging. the flier a fairly experienced warbird RCs had quite a problem landing it as it had to be landed "hot". Just my 2 cents
kind regard..
10-11-2005, 06:34 AM
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RE: FUN SCALE MOSQUITO - MY FIRST TWIN
Hey EF and Martin,
Thanks for your replies and I will certainly keep the flying tips in mind. My bird is about 85% built at this stage and I'm keen to know if I should put a gyro inher (maybe a Futaba GYA 350 or something similar?).
I've managed to obtain some 1/12th scale pilots from Canada and scale 90mm (3 1/2 inch) spinners from the UK and she is really looking the goods. I've resprayed her with Monokote fuel resistant paints and covered her with a flat clear Monokote lacquer to strengthen the surface (I thoiught it was a bit susceptible to damage in the hangar).
I'll upload some pics when I get the chance.
Dave
Thanks for your replies and I will certainly keep the flying tips in mind. My bird is about 85% built at this stage and I'm keen to know if I should put a gyro inher (maybe a Futaba GYA 350 or something similar?).
I've managed to obtain some 1/12th scale pilots from Canada and scale 90mm (3 1/2 inch) spinners from the UK and she is really looking the goods. I've resprayed her with Monokote fuel resistant paints and covered her with a flat clear Monokote lacquer to strengthen the surface (I thoiught it was a bit susceptible to damage in the hangar).
I'll upload some pics when I get the chance.
Dave
10-11-2005, 08:44 PM
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RE: FUN SCALE MOSQUITO - MY FIRST TWIN
here are some pics as promised
you may note the slightly changed paint scheme - I have sprayed it and covered it with a flat matt clear to protect an otherwise unacceptable (in my opinion) delicate surface which suffers hangar rash far too easily!
you may note the slightly changed paint scheme - I have sprayed it and covered it with a flat matt clear to protect an otherwise unacceptable (in my opinion) delicate surface which suffers hangar rash far too easily!
