Scale Don Smith P-51 Mustang

[stangflyer]

A new development on the Big Mustang today. I have been in contact with Erwin Muller who built his own prop reduction drive unit for his Focke Wulf 190 powered with a "dub" 110. At present, I am attempting to talk him into building a second to fit the Mustang. Long shot, but worth a try. Who knows, the Behemoth Stang just might get a four blade prop after all.

 

[dhal22]

A new development on the Big Mustang today. I have been in contact with Erwin Muller who built his own prop reduction drive unit for his Focke Wulf 190 powered with a "dub" 110. At present, I am attempting to talk him into building a second to fit the Mustang. Long shot, but worth a try. Who knows, the Behemoth Stang just might get a four blade prop after all.

Is it flying yet?

 

[stangflyer]

Is it flying yet?

Haha... very funny.

 

[Snoopy1]

A new development on the Big Mustang today. I have been in contact with Erwin Muller who built his own prop reduction drive unit for his Focke Wulf 190 powered with a "dub" 110. At present, I am attempting to talk him into building a second to fit the Mustang. Long shot, but worth a try. Who knows, the Behemoth Stang just might get a four blade prop after all.

That looks like a nice setup and well built. It will also add some weight to the front which a warbird can always use. Hope you can get him to build one, if not try to get the cad files or drawings off him, then at least you have a start.
Spent some studying the video frame by frame looking at the design and how he did it. He did a nice design simple and effective the only thing that I have some reservations on is the belt that drives the prop is a flat belt. It would not take much for it to slip the tension setup will be difficult and continues.

 

[stangflyer]

That looks like a nice setup and well built. It will also add some weight to the front which a warbird can always use. Hope you can get him to build one, if not try to get the cad files or drawings off him, then at least you have a start.
Spent some studying the video frame by frame looking at the design and how he did it. He did a nice design simple and effective the only thing that I have some reservations on is the belt that drives the prop is a flat belt. It would not take much for it to slip the tension setup will be difficult and continues.

The belt was a concern for me also. I've seen them with "teeth" on the belt. Not as quiet as the smooth belt. But probably never slip.

 

[Snoopy1]

The belt was a concern for me also. I've seen them with "teeth" on the belt. Not as quiet as the smooth belt. But probably never slip.

I have seen then with tooth belt positive ratio and tension is not generally a problem. You can also run a much lower tension in the beltwhen has teeth , and longer life for the bearings and yes they can be noisy. Looking at the design again all that needs to be done to set the tension on the gentleman’s design is to shim the propeller shaft and bearings up.

 

[stangflyer]

Uh oh! Don't look now fellas. I have been talking to Petr Cita of Rotomotor. We've been discussing the Roto 130 FSI the last two days. What an awesome gent. He has emailed me back and forth and never seems to tire of all my many questions. So, it turns out that the 130 turns basically the same size prop as the 3w 110i r2cs. It weighs in at just shy of 3 pounds heavier than the dub twin. Not all that bad. 10.3 vs. 7.69 for the 110. I may have to add weight up front so it is best to make that weight useable instead of just dead weight right? I've also seen a few videos of how they have been set up. One gent swears that the rear cylinder never gets above 215 degrees. Now that is good to hear. I have also been toying with an onboard cooling system for the 110 if that is what is to be. At this time, it still is. But knowing me, it could change. LOL. As for price, $300.00 dollars more than the 110cs. That in itself is almost enough to pull the trigger. But the best of all the reasons, take a listen to this.

High speed pass with what looks to be a P40: (Going so freaking fast it is hard to tell)

An upside is the reviews I have found have been all positive. Though the Roto Motor is not as well known as say the Valach or Moki or even 3w for that matter. It definitely could be a feasible option.

I have plenty of time before I actually need an engine for the Behemoth Stang. I just don't want to get something and then later regret my decision.

I guess I just can't get past that "mean as hell" sound. I'm pretty certain I will stay with the 3w 110. Maybe for a future project? Like say, Oh I don't know.... A P40 with that mean sound could be cool. What do you guys think? Anyone out there have any experience with the Roto Motors? From all I can find, the company seems sound. Apparently they also build UAV for the military. Hmm....

What do you say fellas?

 

[acerc]

I have seen a few and they are nice. The last time I checked into them the biggest drawback for me was no stateside support, of course that may have changed.

 

[stangflyer]

I have seen a few and they are nice. The last time I checked into them the biggest drawback for me was no stateside support, of course that may have changed.

I believe there still is no USA assistance if required. To me this is a deal breaker. I suppose I could get past it if the engines had more usage by us 'Merican RC Pilots. I would be afraid I would be in the same boat as I would be with the Kolm.

 

[Snoopy1]

Looks like a nice machine but have no experience with the motor but they have been around for a while. Sounds great but on this one I cannot help you sorry. But with the price that close to the 3W and it is four stroke that makes it very interesting.