Ok, case is I have two MVVS .21 laying around and been thinking of some time to build a twin engine plane for those. So if someone has nice drawings to send by email or if you know a website where is good drawings I would like to know


Email: [email protected]

You might want to bench run those motors first to see if you are going to like them. I had really bad luck with my only MVVS engine, and ended up trading it to MOECA for one of their motors. I've not read any good stuff on them either, but check around first. R/C Report really trashed them, and not the only folks to do so. You will need dependable engines on a twin, or you will lose your model.

Bench run the engines and do so until you can hold a peek rpm (or a touch rich in peek) with out over heating, and also have a solid idle. A good transition is needed also with a twin, three or four banger. After you are satisfied each engine is running good, I put mine on an engine stand together, hooked up to a common throttle, and run them that way to see what I have (I check peak RPM, over heating, idle and equal transition). Getting all the problems ironed out prior to installing them is important. Then setting them up is the next chore, and take time to set up servo arms, cables ect. as even as you can. I put easy connectors on my carbs. so to make easy ajustments. I also make sure my servo arms line up equally and install my throttle push rods evenly and the same way-you will be surprised at the difference between servo's, even good servo's. I learned the hard way, and even have had to cut into my wing to re-build my throttle servo linkage on one of my first twins. I now run one servo to one engine...accept on my small model twins, and that is for weight savings. I also had a cooling problem with one model that I no longer have...for I stuffed it in with an engine failure-so nacelle aerodynamics is important too, even after a good break in-but if you run with your engine heads in the wind, little or no problems here. So even if all goes together well, test run your model for several tank fulls on the ground first. You can time your engine burn at full throttle, and set up your radio (if you have a timer), to let you know when you have low fuel to land your model. Dead stick twins drop like rocks, and with out the tail feathers in the prop blast, less authority in this flight area too.

I never detune, or tweek my engines to eachother...never. I run each engine by itself, and set it to itself to run it's best. Then tack the engines and listen. Listen to what you have, and use your tack. Just thoughts on what I've learned the hard way over the years...

Multi engines are sweet music, and always grab attention, not to mention just plane cool...

Soft landings always,

Bobby of Maui

Thanks for the information. Well I know those small MVVS engines are not the absolute best for twin use, but at the moment I dont have any other two similar engines to use, so why not use them. All the building an setups is no problem.

Henri, I run several of the MVVS .21's in my single engine planes and I have two in my Morris Twin Trainer and two in my VQ A-26 Invader. I've had excellent results with them. The MVVS .21 has excellent transition and throttle response and has an excellent idle. The MVVS .21's are probably one of the best engines you could possibly put into a twin.

MVVS also offers a counter rotating crankshaft for the .21 and you can rotate the exhaust of the engine to either left, right, or rearward. This feature gives you a bunch of possible design and installation configurations.

You could have both heads facing inboard to keep your weight inboard and have both exhaust facing downward or rearward and have one engine with reverse rotation to offset torque.
Pretty cool configuration for a twin!

We have a video tape of the Twin Trainer with two MVVS .21's in a solid hover about 6 feet off the ground and then we do a tail touch and then go back into the hover. We've sold thousands of the tapes so many people can attest to it! It's a fun tape to watch.

The MVVS .21 is one of our best selling engines of all times. Most people have excellent success with them. The engine has a great warranty, we have great service, why Bob Paris couldn't get his to run is only a mystery to me. We are a phone call away or he could have sent the engine in to have us look it over for him.

Mr. Paris, I always hold people accountable for what they say and do, perhaps you should call me privately at (281) 364-8011 and we could discuss your situation, rather than you trash my product and reputation. Mr. Paris, I can't model for you, but I can put good equipment in your hands, and hope you have the ability to do the rest.

Respectfully,

Robert Kozak
President
MVVS Corporation of America

Jup I know those MVVS .21 are really good engines and powerful to their size. I havent have any problems with them. Im still keen to have some drawings(cad, pcx, gif...) to start a project.

Dear Robert;

I did not intentionally trash your companies engines, but my luck with your engine is fact for me, and what I stated in my post. My information was earned over five years ago with your engine, and R/C Reports Magazine stated the same...and came out with their confermation/artical about the same time. I do not know what has taken place with your company over the past several years, and in my post I did state that he should bench run them first to see what he has. I've had problems with both my MVVS engine, and Fox motors. I've experience with Cox, OS Max, Enya, Super Tiger, MOCEA ( suprisingly strong and inexpensive),and my best engines, K & B. MVVS at that time did not do me justice, and I did try every trick in the book that I knew of, to get it to run reliably.

To be fair to you I will state that it was Five Years Ago that I delt with your engine, and I do not have any current information on your motors. I also get just about every model airplane magazine published in this country, and have no current information about your engines one way or the other...

I also work out side this country, and home one to three months a year. At this time, I did not have the time to send in motors that did not work, or any model products, and try to correct any problems that I may have had with them...and I can not say enough good about Robart or K & B. Most all companies have done more then expected in honoring their products, and I've issues with Ace r/c and Hobby People. Hobby People just blew me off, and Ace is still working to resolve issues with some of their electonic products, and no help with their Fun Fly ARF stabilizer failures...I've had two fail on me.

That MVVS was an inexpensice motor, and decided not to fuss with it any more. I did not turn in the engine to anyone for repair, and have no idea of how your company would have responded...but by your strong wording in your letter to me, you seem to take this quite personally. I've no idea if you were on hand five years ago with these engines or do I have any current informatin on them...as I stated in my Post...Bench Run them first, and see what you get...

Soft landings Always,

Bobby of Maui

I have own those engines several years now(flyed 1:12 aircombat a few years with em) and I know what I have, but thanks anyway about the information and tips what I should think when building a twinner. Robert Kozak: I think you have managed to build good and powerful engine. I havent had any major problems with em and alot of pilots uses MVVS .21 power plants in combat here in Finland. This is getting a bit out of the subject.

I sitll would be grateful if someone has a drawings to .21 size twinner. :stupid:

Henri,

For fun-fly twins, you might want to check out the Morris Hobbies "Pinwheel Twin" and the "Morris Twin Trainer". You can buy the drawings and building instructions with a complete set of ribs for $34.95.

Both airplanes were designed around your MVVS .21 engines with mini-tuned silencers. As discussed, the MVVS .21 has the extra advantage of having a rotatable exhaust, so that both engines can be configured to point in-wards, while both mufflers face downward.

The Twin Trainer is the easiest twin in the world to fly, even on one engine! You can take off, land, roll, spin, etc...(on one engine)! It's all on the video tapes. The Morris Hobbies airplane tapes are worth watching and you can return them for credit on your order.

Do you have VHS or PAL Video format in Finland?

You can see the details of both the "Twin Trainer" and the "Pinwheel Twin" at the Morris Hobbies website:

http://www.morrishobbies.com/product...5ad452a2af9e60

The "Pinwheel Twin" flies as easy as the "Twin Trainer" and is capable of doing outrageous "Pinwheels" and other Hoverbatic maneuvers like flat spins, inverted flat spins and cartwheels!
Excellent knife edge, and even vertical hover are standard features with this airplane/engine combination.

There is a "Morris Mixer" available that with give one engine full throttle and put the other engine at idle when you apply full rudder. This makes the spins really tight, like you can't believe!

Be sure to check out the real nice VQ ARF Twins if you visit the website. They have the A-26 and P-38.

Hope that helps! Just a suggestion.

Sincerely,
Robert

Well Im 100% self builder, but nice looking planes those are anyway! Thanks for the suggestions and other. But I keep looking. Oh the video system is PAL..

Henri,

I think you can get just the plan sheets for $15.00

Robert

Okey

Henri:
Are you looking for 3 view drawings, or are you looking for plans to build from?
I have a few pages from the Aerocommander 680FP (full scale) maintenance manual which includes a spec sheet, 3 view with dimensions, cowling, landing gear, instrument panel, and other details.
I have built a 50" span model from these drawings for a pair of OS15s, the model was a beauty and flew great - and that was over 20 years ago. (Lost the airplane to transmitter battery failure).
I do not have plans for you to build from for your MVVS.21, but if you can design and scratch build, you might like the Aerocommander 680FP.

If you can send the 3views by email I would like to chek em.

You can find some twin drawings on http://plans.rcmodell.hu/

Jep, two kind an interesting drawings downloaded...