Aviomodelli Skymaster--Gas Engines?
08-20-2005, 12:56 AM
#1
Aviomodelli Skymaster--Gas Engines?
I'm going to order the Aviomodelli Skymaster 50% ARF (kit).
(NO, I don't want the fiberglass KMP ARF. I'd prefer to build a kit and place my servos where I want for best weight advantage and control authority. I just dont want the KMP--so it's not an option here.)
The Aviomodelli Skymaster has about 1100sq.in. of wing and weighs about 13-15 pounds. Looks like about 7--9 servos depending on if I build flaps into it (most likely) and a retractable nosewheel (maybe--I'll have to get the kit and look at it before making a decision on that. But it would be cool). I don't think 13-15 pounds is unreasonably high wing loading for a scale plane with 1100 inches of wing. It's not being built for 3D.
I really don't like the idea of using glow engines on this plane. Given my altitude, it would take at least a couple 1.00 glow engines to get good performance. Maybe even a couple 1.20 glow engines.
I believe the airframe can handle a couple little gassers. I was looking at the Roto 25 or the RCS 1.4 or the MVVS 1.60 for this plane.
I've never owned any of these engines, and I'm sure they all have their strengths and weakness'. I don't want a discussion on which engine sucks or which one is the best.
I'm looking for opinions about actually using these gassers on this airframe. I'm a little concerned about the added weight of the gas engines, but I think I can build the plane light enough to compensate for it. I've done it before. Building light is just a matter of replacing some ply with balsa, and keeping the glue under control. A couple strategically placed lightening holes is always a good idea too.
The RCS 1.40 (22cc) weighs 2.8LBS RTF with muffler, ignition, switch, battery. It costs $475 by the time you put a muffler on it.
The Roto 25cc (1.5cu.in) weighs 2.8LBS and costs $440 with a muffler. I think this weight is with all the accessories--but not POSITIVE.
Both the RCS and the Roto are rear drum inducted. Better power IMO.
The MVVS 1.60 (25cc) weighs 2.3LBS bare bones and costs $450 with a muffler. It's probably within an ounce or two of the other 2 engines RTF with all the accessories.
The MVVS has a front carb and pulls fuel into the front of the crank like a glow engine. Not the best power--when compared to a drum induction like the RCS and Roto.
They are all within $50 on price and they all weigh about the same.
I'm leaning towards the Roto 25 simply because of the looks and what I've read about it recently. Seams there have been a couple ignition problems with the RCS 140. I wouldn't mind trying the MVVS engine, but kinda wanna try the Roto 25 MORE. I like the CNC machined cylinder, and the blue cylinder head. I plan to paint/cover this plane in primarily blue anyway--so it will look kinda cool with blue cylinder heads in the cowls.
The fact that you can turn the cylinder on the RCS 1.40 might be handy if space got tight inside the cowls. You could make it rear exhaust and clean up the muffler and installation if needed.
The Magnum 120 weighs 31oz.
The OS 120 Surpass non-pumped weighs 33.3oz.
The OS 120 Surpass Pumped weighs 35oz.
The Saito 1.00 weighs 21oz.
The Saito Twin 1.00 weighs 29oz w/o/ mufflers
The Saito 1.20 weighs 28oz. w/o muffler
I won't even list weights for .91 glow engines. They are NOT going to be enough power to fly this thing in Colorado.
I figure that--on average--these glow engines weigh around 1LB less than the gassers I have in mind. So, with 2 gassers, I'll be adding 2LBS of engine to the airframe. Maybe 3 if your comparing 2 Saito 1.20s too 2 of the gassers. That shouldn't be hard to build out if I replace the ply fuse sheeting with balsa wherever I can get away with it. I rarely use wheelpants or cockpits/pilots. So, I can save weight there too.
What do you think?
(NO, I don't want the fiberglass KMP ARF. I'd prefer to build a kit and place my servos where I want for best weight advantage and control authority. I just dont want the KMP--so it's not an option here.)
The Aviomodelli Skymaster has about 1100sq.in. of wing and weighs about 13-15 pounds. Looks like about 7--9 servos depending on if I build flaps into it (most likely) and a retractable nosewheel (maybe--I'll have to get the kit and look at it before making a decision on that. But it would be cool). I don't think 13-15 pounds is unreasonably high wing loading for a scale plane with 1100 inches of wing. It's not being built for 3D.
I really don't like the idea of using glow engines on this plane. Given my altitude, it would take at least a couple 1.00 glow engines to get good performance. Maybe even a couple 1.20 glow engines.
I believe the airframe can handle a couple little gassers. I was looking at the Roto 25 or the RCS 1.4 or the MVVS 1.60 for this plane.
I've never owned any of these engines, and I'm sure they all have their strengths and weakness'. I don't want a discussion on which engine sucks or which one is the best.
I'm looking for opinions about actually using these gassers on this airframe. I'm a little concerned about the added weight of the gas engines, but I think I can build the plane light enough to compensate for it. I've done it before. Building light is just a matter of replacing some ply with balsa, and keeping the glue under control. A couple strategically placed lightening holes is always a good idea too.
The RCS 1.40 (22cc) weighs 2.8LBS RTF with muffler, ignition, switch, battery. It costs $475 by the time you put a muffler on it.
The Roto 25cc (1.5cu.in) weighs 2.8LBS and costs $440 with a muffler. I think this weight is with all the accessories--but not POSITIVE.
Both the RCS and the Roto are rear drum inducted. Better power IMO.
The MVVS 1.60 (25cc) weighs 2.3LBS bare bones and costs $450 with a muffler. It's probably within an ounce or two of the other 2 engines RTF with all the accessories.
The MVVS has a front carb and pulls fuel into the front of the crank like a glow engine. Not the best power--when compared to a drum induction like the RCS and Roto.
They are all within $50 on price and they all weigh about the same.
I'm leaning towards the Roto 25 simply because of the looks and what I've read about it recently. Seams there have been a couple ignition problems with the RCS 140. I wouldn't mind trying the MVVS engine, but kinda wanna try the Roto 25 MORE. I like the CNC machined cylinder, and the blue cylinder head. I plan to paint/cover this plane in primarily blue anyway--so it will look kinda cool with blue cylinder heads in the cowls.
The fact that you can turn the cylinder on the RCS 1.40 might be handy if space got tight inside the cowls. You could make it rear exhaust and clean up the muffler and installation if needed.
The Magnum 120 weighs 31oz.
The OS 120 Surpass non-pumped weighs 33.3oz.
The OS 120 Surpass Pumped weighs 35oz.
The Saito 1.00 weighs 21oz.
The Saito Twin 1.00 weighs 29oz w/o/ mufflers
The Saito 1.20 weighs 28oz. w/o muffler
I won't even list weights for .91 glow engines. They are NOT going to be enough power to fly this thing in Colorado.
I figure that--on average--these glow engines weigh around 1LB less than the gassers I have in mind. So, with 2 gassers, I'll be adding 2LBS of engine to the airframe. Maybe 3 if your comparing 2 Saito 1.20s too 2 of the gassers. That shouldn't be hard to build out if I replace the ply fuse sheeting with balsa wherever I can get away with it. I rarely use wheelpants or cockpits/pilots. So, I can save weight there too.
What do you think?
