Smoky

hot rod thanks for the quick reply,, I will change up to the 11x7, or 11x6 and a 3 inch spinner. then with the extra weight I can remove some from the nose.

Hot Rod Todd

My Feedback: (1)

I would not use 11X7's on you .40's, that would be too much. The 11X6's should work fine.

Sandmann_AU

You're lucky yours was separate. I'm having to scratch all the silly decals off mine.

Err.. no. My understanding is that it's not only exposed blade that's critical (thought it has some effect), it's also rotating mass. Covering the centre 1.5" of the blades doesn't mean you can make the blades 1.5" longer with no effect.

However the difference between covering 1.25" and 1.5" (using a 2.5" or 3" spinner) of the least most effective part of the prop blade is insignificant. Think of prop blades as wings (which they are really). The faster they move the more lift (or thrust in the case of props) they provide. However the centre of the prop is the slowest moving part of it. Also anywhere near the centre of the prop the air's just a whirling mass of drag, due to the blades moving in opposite directions at such close proximity. This is why we use spinners in the first place, to direct the useless air mass where it'll actually be useful.

Should be fine, many folks use 11" props on your engines. If you're doing 17,200RPM when loaded up on the ground chances are you're already at (or over) max RPM. A little extra load from 1" longer props would be fine. You will lose a little rotational speed but it'll be offset by increased thrust.

david polley

Dear Smokey, Hot Rod Todd

Wow, your model sure does look like a CMP kit. Is the "Genreral Hobbies" name just a cover front for what is really a CMP kit?
I am still concerned in that your instructions said the balance point was 130 to 135 mm. The CMP plans stated between 115 and 120 mm. If everything appears to be what the plans you have stated, then maybe a good balance point to start would be at the 125mm point. This would 5 mm closer to the leading edge on your model, like it would be on the CMP version at the 110 mm point.

I just think 21 ounces of nose weight is too much....

About the spinners, I used Dave Brown 3 1/2 spinners using two O.S. 40SF engines runing Top Flight's 10 x 5 power point wood props. No problem with the engine / spinner combination. In fact the large spinners made the engines really run smooth at a very low idle setting on the carburetors The openings on the carbs were closed to the point where I could hardly see an opening. The "free wheeling" effect is pretty cool. The only problem I had is I had to use the 10 inch props which does not make the model look scale when they are running. 11 x 4 props were very disappointing.

I have decided to rebuild two O.S. 46FX engines and run 11 x 5 wood props. The 46FX engine is actually lighter than the older 40SF engines so I will have to take another look at the CG when I get finished.

Is your wingspan 73 inches? The CMP wingspan is 73 inches. I am really curious...! Is this a CMP kit in disguise?

Hot Rod...! What do you think about the CG on Smokey's model?

David

Hot Rod Todd

My Feedback: (1)

CG is about the wing. Without checking the wing to see if it is the same shape and size as a CMP kit it is hard to compare. My first CMP Mossie I added over two pounds to the nose to get the CG everyone said was "right." Once I removed some of the weight on the second model it flew much better and did not feel so nose heavy. Even so, there is no such thing as too much nose weight, you must add whatever it takes to make it right. The problem with Smokey's plane is that we don't know where the right balance point is located. Unless the wing has much more cord, I can't see 130 to 135 mm as being even close. I'm not sure where I am right now with the balance on mine, I know I posted it somwhere way back in this thread. Someone should take accurate readings on the CMP wing dimensions and post them so he can compare.

I would not run 11X5 props on twin .46FX's. Every fighter I put a .46FX on I found the 11X6 MAS to be a great match. On a mossie you might even go the extra pitch and run 11X7's. They ended up being much better than the 11X6's for my plane. The AX has just a bit more power than the FX, but they are so close that I think you would get simular results. I must admit I don't know how the thicker wood props would perform since I don't use wood props. With two .46's this plane goes fast enough to significantly unload the engines. If they wind up too high the correct needle valve setting is harder to maintain and could lead to an engine out situation (not good). Just be careful you don't go too fast when the nose is pointed down, the rudder likes to flutter and has caused a few crashes as evidenced by Youtube videos.

SJN

I need to get one of these one day.....


Found some nice pictures showing that this actualy is a wooden plane....

david polley

Dear Hot Rod,

My only goal with the 46FX engines and 11 x 5 props is to get her in the air much faster than has been the case with my old set up.

The 40SF engines ran great once I got her in the air, but she lumbered down the runway, of which I needed most of it, to get the back end to lift up with almost full right rudder.

The challange with me has always been fighting all of the forces on the ground until I got enough air speed to actually have the rudder start working and only then did I have the control I needed to get her off of the ground. At the GCRCC 50th anniversay model Air Show we just had in August, the direction for our "Normady Invasion" had already been established to take off to the west with a 20 to 25 mph near cross wind coming out of the south / southwest direction.

We were flying 20 models during the recreation, complete with all of the fireworks, explosions, collapsing buildings, water cannons and so on. It was so cool, but even with full right rudder and an 80 foot wide runway I still could not overcome the crosswinds at the moment I was told to go. I could not get the mossie up in the air the first time. [&o]

The tork on the engines pulling the model to the left aided by the 25 mph cross wind pushing on the rudder did not let me get her up on the first try. Had I been able to go west, the the winds would have easily kept the model on the runway since the wind then would push against the tork of the engines. However, having to take off 20 models in a minute or two mandates that once the take off direction has been established, it can not be changed, so I was forced into the situation I was in.[sm=red_smile.gif]

I finally got her up on the second try when the winds went back to the southwest direction just long enough for me to get enough speed and get in the air....[8D]

Sooo..... I have decide to go with the more powerful engines and larger props to overcome this problem if it develops again. I will then throttle down and cruise at 3/4 throttle or even half throttle if I need to to keep the model flying and looking more "scale like" in the air. I just need that extra "punch" to get her in the air more quickly.[sm=angry_smile.gif]

I have also already beefed up the rudder. I removed the film and glued with epoxy, 1 /64 inch plywood skin over the very weak stick set up they had on the original rudder. I then used a very low heat red film called "Valkote" made in the late 70's to cover the rudder area. Now even if the plane flips over from a bad landing or take off, the rudder will not break....

Montague

I have OS .46AX's in mine. The FX and the AX aren't that far apart in power, and the SF isn't far away either. I wouldn't hesitate to put 11x6 or 11x7 props on either.

I'm using APC 11x7 props. The takeoff has to be done carefully and it takes a while to accelerate the model, but once up to speed, it clips right along (usually out running the other simular size warbirds at the field easily, I was clocked at just over 100mph level flight once).

I started with APC 11x6 props. With the 11x6, the take off was noticeably shorter, and the climb faster, but the top speed was lower and I wanted to go fast .

The mossie is a clean, rather low drag airframe, and the CMP version isn't half had on drag, so once you get things rolling, the props can really unload. If you're turning around 17k or more on a .40-.46 engine on the ground, you're probably not unloading much in the air, so all that nice clean airframe is going to waste. Last I checked, I think I'm getting around 11-12k on the ground, and there is a noticeable unload (which means that leaving the engines slightly rich on the ground is a "must" otherwise there's not enough fuel for that unloading, and the engines would go lean).

Be sure to double check that CG, that Mossie kit does look like the CMP that I and others here have.

I can't wait until the VA warbird museam down near Virginia Beach gets their Mossie in. I suspect those pictures are from that restoration. You know I'll be heading down there to see it up close. And I do think it's somewhat ironic that my model of a ply-and-balsa full scale is made mostly from fiberglass. (If I recall correctly, the fuse in the full scale Mossie is laminated ply and balsa layers).

Smoky

thanks for all the input!
I put a fresh battery in the Globee tach, and they ARE running at 11,200 RPM. NOT the 17,200 as I stated earlier.
I apologize for any confusion this may have caused.
when tuning they hit 11400, then richen up to about 11200 to compensate for lower fuel levels and nose high attitudes which similate a lower level in the tanks.
The manual that came with this plane was almost useless, so I DL a CMP manual and it fits the model pretty much to a tee, except for the divorced belly pan and a few other things that come allready presassembled in the CMP kit. at a glance, you can't tell this plane apart from the other.
here is a photo of the plane I saw when I bought it. As i stated earlier i think the General is a knock off of the CMP or Nitro model.

The nose cone comes off with 4 screws so I can easily adjust nose weight.
I weighted it today, the AUW is 13 lbs, and the wingspan is 73 inches.
I will take some more photo's at her maiden flight and hopefully a video.

thanks again for your help.

Smoky

Maiden Flight:
you tube video to follow, probably in about a week, as I am working.
15 Km/hr wind gusting to 25km/hr. cloudy. 18 deg C.

Plane balanced 115 mm from leading edge next to cowl. almost perfect,, the way she handles.
Many thanks to all of you folks for helping with that. If I would have tried to fly it at the 135 suggested balance, it would have been a pretty short flight.
Took her out the grass runway. fired it up, dialed in the needles, actual reading was 11,900 and 12,400, so richened the 12,400 down to about the same RPM. still swinging the 10X6 mas props.

Taxi was pretty much straight forward, held up elevator to keep tail wheel down until the rudder could take over, when up to speed let the tail come up and held her straight until she had a lot of air speed, only then did I let it come off the ground.
(Thanks to some youtube videos i've seem where it lifts too early and does a slow roll into the ground).

3 clicks of of up elevator, and 3 clicks of right aileron. and she was flying level. brought it around gained some altitude and speed, and then raised the wheels. she pitched up a bit, so gave it 2 or 3 down trim to level it. Then she proceeded to hit what felt like mach 1.
This bird is fast.
about this time i was vibrating pretty good from the excitement. You really have to watch this bird as it is a handful. (I may add a bit more nose weight).

Done some level turns, a barrel roll. and a snap roll. all flawlessly.

I then throttled back to about 2/3 throttle. all seemed ok.
about this time I was getting concerned about fuel level. so brought her in high and went to hit the flaps but dropped the landing gear instead. this was a good thing. because my mechanic (me) forgot to loc-tight, some set screws on the left gear, the strut and wheel
enjoyed a free flight to the runway. Now I just have to land the rest of the plane!!! bugger

Made another circuit and brought it in for a belly landing,, boy this thing will not fly slow at all. it ended up being a pretty good landing though I've seen and done better. AS soon as I cut the engines, it stalled from about 2 ft up, nosed dipped and it was in the grass. Still all in one piece, (except the wheel that landed first) LOL.

I have to check the Video for actual run time for fuel levels. (I think between 6 and 10 minutes), but when I went to drain the tanks after, one tank was EMPTY and the other had about a bottle cap worth left in it! Talk about a close call. I know this thing will NOT fly on one engine!

Awesome flight and again thanks to everyone here for their help.

Next I flew the Super Skybolt, tailspins, knife edges, you name it.. It seemed tame compared to flying the Mossy.
It was a very successful day.
PS the thrill of flying this Mossy, made it more than worth the frustration of building it! I would do it again in a heartbeat!

Montague

Congrats on the flight and good thinking about loosing the gear.

Try using the flaps, but be very careful. I deploy flaps when the engines are at idle, on my high downwind leg. I usually use half flaps early on, then bring in full flaps as the speed slows. I don't need any flap-elevator mix. However, be very careful on go-arounds with flaps down. On my Mossie, adding power with flaps down results in a hard nose up and no increase in airspeed. Basically, if I just add power and do nothing else, it will pop right into a stall. So I raise flaps while bringing up the power, smoothly and slowly on both. Which means thinking way ahead in terms of deciding if I'm going to land or go around.

Also, be careful about using the mixture to set engine RPM. That's one thing I Never do with twins, it's just asking for an engine out because an engine is too lean or too rich to transition smoothly. I don't worry about peak RPM on my engines, they actually do a good job of synching themselves in the air as the more powerful engine pulls a bit harder which unloads the weak engine. It's more annoying on takeoff than anything. However, if you really want the engines to be in synch on the ground, use the throttles after setting the mixtures in the "normal" way. This is to ensure each engine is running in the most reliable manner possible.

Hot Rod Todd

My Feedback: (1)

Good job on your maiden Smokey! I concur with Montague, I would never mis-adjust one engine just to have it match the other. Set them both at the best point to prevent an engine out. A bit out of sync at wide open will not matter. Make sure the low end needles are set good enough that both engines respond cleanly. If one ramps up quicker than the other it can make take-offs even more difficult. The mossy can fly on one engine (or at least survive). I had an engine die shortly after climb out (The glow plug fell out due to me twisting the glow igniter off and making it loose). I backed off throttle and was able to land the plane on one engine. I would not recommend single engine flight, but the Mossy is better than a P-38 if it does happen.

For landing, I use full flaps every time. It helps slow the pig up when the nose is pointed down. I wait until the nose is pointed down before I go to full flaps. I believe I have a slight amount of down elevator mixed in with the flaps.

Smoky

thanks for the Info Montague!
for some reason, I never considered using the throttles to sinc, I will try the throttle thing, I like it. and thanks for the heads up on the flaps. That is what I was intending to check out when I hit the wrong switch and dropped the gear, Literally.
So with this plane, correct me if I am wrong, you have to literally fly it to the runway, about 1/2 throttle, before cutting the Engines, correct?
I ask this based on what it did when i was going to belly skid it in, and how fast it dropped when i did cut the engines. I wasn't expecting such a quick drop.
Fortunately it was low enough it didn't hurt it.

Hotrod: I will go full flaps and nose down on the next flight. I didn't get a chance to really do much with it flying slow, does the control soften up a bit a slower speed? It is very responsive a full speed. Did I say how fast this thing was? LOL

Montague

Actually, I don't use a lot of power on approach because of the way the flaps interact with the thrust. I tend to set up high and bring the power back and keep it pretty far back, flying on the bottom 1/4 of the throttle range to adjust my approach when I have the flaps down. I keep the airspeed off by setting up high and coming downhill until I get just off the end of the runway.

You can fly it in with power, but the flaps will cause a lot of nose up with power, so you'll have to hold the nose down.

When I'm downwind and high, gear down, power back. As the speed bleeds off (takes forever), the nose starts to come down. I add half flaps and not elevator. Then as the speed continues to bleed off as I do a descending turn to the end of the runway, I'll add full flaps when the plane starts to again lower the nose too much. Again, I'm using the flaps and not the elevator. My elevator is pretty much fixed at center through the entire approach right up until I use just a hair to get the nose up to level before touchdown. (I never three-point my Mossie, my stall tests at altitude convinced me that nose-up and slow was a bad idea).

If you do get too slow, the stall is very sudden and violent, with no warning at all, that's for sure. I scared the living daylights out of myself when I did my first high altitude stall with it. It slowed nicely, lots of control, no issues, then *pow*, it snaprolled inverted and dropped the nose. Took a ton of altitude to recover as well. My Mossie is the only model I have that I don't spin. (or snaproll either for that matter). I keep the speed up and the nose down .

Oh, I did loose an engine once on my Mossie. I was trucking downwind at full throttle right to left, about 50feet up and just on the far side of the runway, doing a high show pass when I heard an engine quit suddenly. I pulled the other engine to idle, left the gear up and flaps up, and flew it like a deadstick, using my existing airspeed to get a little altitude, turning out a little then back to the runway, half flaps part way through the turn. Since I looked a little short, I gently blipped the throttle to streach the glide while wings-level and nose-down. I only lowered the gear after I was over the runway and about to touch down. I never figured out which engine was dead until I could see that the left prop wasn't turning right before touchdown. I'd turned towards the dead engine with out knowing it, but it didn't matter since I'd kept the airspeed up the whole time. Stay in a fast power-off glide when single engine, and you'll be fine. Don't try to power up and climb or go around, and don't get low on airspeed and high on power and you'll be fine. All twins have a Vse, Velocity, single-engine, the airspeed you must maintain while on a single engine to maintain control of the plane. On my Mossie, it's a lot higher than on my Duelist (which is really easy to handle on one engine, but that's another story).

Hot Rod Todd

My Feedback: (1)

The technique Montague described sounds much like what I have found. How much throttle on landing will depend a lot on your altitude. Any time you point the nose down on the mossie it tends to pick up speed. I use 11X7 props, so I can get quite a bit of thrust even at lower RPM's. I would say I tend to drop the RPM pretty low and use the momemtum to make it to the landing point. Too much RPM combined with decent on landing with my set up and the thing will not slow up.

Smoky, if you think yours is fast you should try two .46 AX's with 11X7 props. I can break 100 mph at half throttle (which we all know is much more than half power). Even so, I tend to cruise around at partial throttle and only go to full when the nose is pointed up.

Smoky

My first published You tube video,, for your entertainment only,, The shortened version of the Mossies Maiden Flight.
according to the time frame of the camera, the Engines ran for 16 minutes and it flew for 14 minutes.
it felt like only 5 or 6 minutes though.

http://www.youtube.com/watch?v=ii0t3yfRPhM

david polley

Dear Smokey,

Congratulations[sm=teeth_smile.gif] [sm=teeth_smile.gif]

I am so glad you got your bird in the air. Great job on the taxi and take off. I am sending along the link I wrote on Post 768 about setting up the engines and tuning them up together. As strange as it sounds I have not had the pleasure of using a tach to measure the RPM on my engines, but have always just listened carefully to get them to match up. Basiclly you just set up each engine independently, especially the mixture screws on the carbureters to have a clean and "instant" transition from you idle settings to maximum rpm. Make shure your throttle linkages are mechanically set as close as possible. On your first flight of the day at the field, you set one engine and get it running normal. Then shut it down and set the other engine the same, both of which should be slightly rich. Then run both engines, hold the model 45 degrees in the air, wait a minute until the engines come up, then back down the higher running engine, (usually just one click) until it matches the other. Refuel both engines and you are ready to go.
Post 768 is pretty detailed, but it has always worked for me with engines that have mixture controls and throttle stop screws.
The link is:
http://www.rcuniverse.com/forum/fb.asp?m=8441400

I have also attached the link from youtube of my model. You can hear how the engines are running in the idle settings and full rpm. The link is:
http://www.youtube.com/watch?v=zZPewtLpsCE

Great Job

David

david polley

Dear All,

I just released a new video from our 50th anniversary Flying Circus that I flew in on August 7th, and 8th, 2010 here near Cincinnati Ohio.

A very good friend of mine shot the video of several of the models at the airport that day including yours truely running up my engines on my Mosquito. Since I had to do the sound behind the flight line, this was the only time I had to prepare the mossi for the days flying. He was very interested in how the engines ran, and I just wanted to share it with all of you.

This gives you a little taste of what the Air Show is all about here in Cincy [sm=regular_smile.gif]

The web site is:

http://www.youtube.com/watch?v=KPuDOZsQOQY

Smoky

Great video!! thanks for posting it. Is that your wife behind you with the camera?

On a not so great note, here is a little story.
Some Idiot (me), programmed 15% flap to elevator offset to prevent a nose up pitch.
tried flaps on my second flight and it dove instead,, i was up high and about 1/2 throttle. no problem.
tried to keep it level at low speed but had to hold an aweful lot of up elevator. Too Much.
I decided to land without flaps, still had about 50mph of speed and no runway left!! so throttled up and went around again.
brought it in shallower this time and slower,,, but too slow.
It dropped a wing, clipped the runway and cartwheeled in.

Busted the wing sections out of the center section, the aluminum tubing gutted it pretty good.
Cracked the fuse, and rudder, and busted one engine clean off.

On the bright side, the landing gear stayed on, and it never busted a prop.
And I've learned from it. experience is what you get when you don't get what you wanted.

I've tried to get a CMP model to replace the General hobbies one,, but no luck.
Jet-hobbies here in Canada is our only dealer, (they ship canada wide), but they are sold out.
Nitromodels and Raidentech have them, but say they are too big to ship to a canadian address. (but they can ship anywhere in the states).
I've tried USPS and UPS. They don't deal with Fed-ex anymore, I've been told.

Does this mean the Gate at the Border is too small?!! I don't get it.

The General hobbies model came out of the states,, and it was here within a week, and it too is a 73" Model.. go figure. it came USPS.

So i guess David I gotta ask you,, If I bought one and sent it to your address, and then you forwarded it to me, I would pay you for your troubles, and expenses, would this be a possibility?
Regards,,
Rick.

david polley

Dear Smokey,

Let me check on my end to see what it takes to send something to Canada from my shop. I will try and work with you.
Yes that was my wife...
I am very lucky to have her in my life. She really supports me and my my hobby.

Why don't you e-mail me at [email protected] and I will check with my shipping guy about sending the model from our office to you. When you e-mail me, I can get a number from you and figure out how I can help from there. When we talk, I can give you my address from there.

So glad you liked the video..

David

Smoky

David:
thanks. I've sent you a couple of E-mails, i don't know if you got them. My E-mail is [email protected] and I am looking forward to hearing from you.
One of my friends here has some CMP model's ( Corsair, P51 Mustang, Zero, and spitfire). that he hasn't put together yet. the quality of these kits seem to be really good.

The only other twin that may come close to what I want is the twin 40 size B52 sold at Great hobbies, although they have a nice Spitfire there too. Perfect for a .91

Rick.

toolman79

Hey just wondering is there any other Mosquito ARF glow kits besides the CMPRO kit?

Thanks

Smoky

there is a smaller electric version i've found,maybe Glow would work on it, but if your in Canada, about your only hope is a General Hobbies Model. and unless you really like building, I would not recommend it.

toolman79

Thanks for the Info Smoky, I have had CMPRO Mozzie but the wings folded on me in mid air the build quality is terrible.

stuntflyr

BH Mosquito's are available with MkVI solid gun noses now at Hobby People.

http://www.hobbypeople.net/index.php...retracts.html#

Chris...