Is an airplane engine an option?

[irlthepearl]

I have a Traxass Nitro Vee on the way from eBay. Back in the day, I did a fair amount of R/C flying and still have a sweet running OS .25 FP. Would this be comparable in power (I think it is rated at .6 hp by OS back then) to more recent engines? It seems like they all have a crazy hp rating.
I am trying to do this without spending much money, but does anyone make a water cooled head that might fit it? We used to run airboats a bit with a water pickup and copper tubing wrapped around the engine. Would this effectively keep an engine cool, or am I likely to burn it up?

[Ozprey]

My uncle has a small R/C airboat, and it runs without any cooling, other than the air off the prop. You shouldn't have a problem.

Peter

[martin richards]

The OS should have spare parts for a water-cooled head. You'll also need a flywheel and a suitable propshaft coupling. I wouldn't recommend running it in a closed space without water cooling. You're also more likely to have problems on many lakes with noise and and other envonmental problems with nitro, which makes electrics more popular these days.

[Ghost 2501]

rather than trying to get a watercooled head, run a belt driven fan off the propshaft, with air ducted to it,

[David Smith]

The FP is very much a soft-tuned sports engine, you may find the power disappointing if you are after a fast boat.

Dave S

[martin richards]

The FP is very much a soft-tuned sports engine, you may find the power disappointing if you are after a fast boat.

Dave S
On the other hand, he might find hyper-critical racing engines equally disappointing if he can't find that elusive sweet spot of prop, pipe length and engine settings for atmospheric conditions ;)
I suppose it all depends on your definition of "fast".

[irlthepearl]

I guess my intent was to make it run with the stuff that I have sitting in my basement as a low budget project (I know that a hobby shop or 2 will probably get some of my money shomehow, but...). I figured that the OS .25 would have roughly the same amount of punch as the factory Traxxas engine, but thought I might get a bit more speed out of it from having bigger displacement and a longer stroke and therefore being able to swing a bigger prop. Is there any sound logic to that? Or am I going to have an overweight, overslow boat?

[martin richards]

The OS 25 weight difference isn't going to be a major factor considering the rady to run weight of the boat. It will probably be more economical on fuel as well as requiring lee nitro in the mix. If your're thinking of using that motor, it's obvious sports running rather than competition is your aim. Your prop comment is justified, especially as you'll be turning at least 10,000 rpm less.
If you want some plain fun, it should give you just that.

[hookpilot]

I guess my intent was to make it run with the stuff that I have sitting in my basement as a low budget project (I know that a hobby shop or 2 will probably get some of my money shomehow, but...). I figured that the OS .25 would have roughly the same amount of punch as the factory Traxxas engine, but thought I might get a bit more speed out of it from having bigger displacement and a longer stroke and therefore being able to swing a bigger prop. Is there any sound logic to that? Or am I going to have an overweight, overslow boat?


I installed an Enya 29 in my 60" Vosper MTB and it worked fine. I installed an Octura Kool Clamp on the cylinder head and routed water from a pickup tube just aft of the prop to the Kool Clamp. It worked fine and was cheap to do. Like you I had an aircraft engine laying around and couldn't justify the cost at the time of 3 electric motors/ESCs, batteries, charger. The only drawback was getting it started with a starting chord and the castor oil mess to clean up at the end of the day. It pushed a 15 lb boat at 18 mph. We ran it next to a full-sized ski boat and were able to get a good speed readout. Lots of vibration to contend with too. Attached photo is the way it looks today with three, 900-size electric motors installed.

Good luck.

[bigfil]

Take a look at http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=5987559324&rd=1&sspagename=STRK%3AMESE%3AIT&rd=1

got some other stuff in store as well

Cheers