TH .75 engine suggestions

Not really familiar with that engine, but sounds like you may have a restriction (some fuzz or a speck of dirt) in the carburetor near the needle valve. You might want to try removing the high speed needle valve and flush the carb out with some glow fuel. Just put your fuel pump on the nipple where the fuel line connects & give it a few pumps, in and out. If that doesn't help, maybe try removing & cleaning the carb. Hope that helps !! Good luck. - Ray

I have a TT61Pro that was hard to start, wouldn't transition, general pain in my tail. All of the 'experts' at the club said it's too rich on the bottom and loading up. Leaning the low end didn't help. My brother and I are not 'experts' and got to the field early one day and richened the low end by 1/2 turn. Hmmm, a little better. Another 1/4 turn, not too bad. A few more little tweaks richer and the engine starts instantly, idles, transitions, an absolute pleasure.

Carrell

May I suggest looking into a comparable electric motor? Much more powerful and efficient, and just plain better.

(potato suit on)

There is no comparable power suppy. Power and duration equal to the .75 would NOT be comparable in cost. It would take MANY gallons of fuel to come near it.

(teflon suit on)

Not true. In fact, I know of two people flying 33% Extras on electric power.

That's true.

And so is that.

The fact is that electric power systems have come far enough that electric power naysayers have little to left to justify there position...well other than cost. On small planes glow power dosen't even make sense when comparing cost.

That said, you'd should have a pretty good working knowledge of electric power systems before you decide to substitute an electric system for a glow .75, or get a lot of help from someone who does.

(Birthday suit on)

I agree, which is why I contend that electric is better. Why else do you always see electric motors on giant scale planes?

(feather boa now in place)

When you say comparable, you have to take in ALL the considerations, not just power.

HUH? You ARE kidding right? Never saw electrics on giant scale.

Well, I wouldn't say they are the norm, but I've seen at least one giant scale electric plane for several years in a row at Toledo. They were different planes....not the same one every year. At this past Toledo show I saw several giant scale electric's including one from Wendel Hostettler.

I'm certain that by now you've heard that several high profile pattern pilots are switching over to electric power. The price for them doing so isn't low, so there must be some other compelling reasons like good power, dependability, consistency, low noise, low vibration which translates to greater dependability of other components on the airplane.

I know in Europe giant scale electrics are far more common than they are here in the U.S. I think noise and fuel costs have driven the European market.

For big planes, electric power is a luxury that isn't easily justified by most hobbyists. But the days of electric powered RC planes being the weak sister of glow powered ones are all but gone....at least for those who care to look at what's possible with electric power.

Wiz

No I don't! I only have to look at the considerations that are important to me. Power is one of them and I think it's one of the top considerations for most people.

In my mind, the only true shortcoming of electric power (in a plane the size a .75 glow engine would fly) is upfront cost. All other considerations deal with personal preference.

Wiz

I don't dispute any of that. What I do dispute is this statement:

Always? How about a very small minority.

We agree on that. Others wer say ing that COMPARABLE E-power is available. I say only if you eliminate cost as a comparisin.

I would tend to agree that there is something in the high speed needle spraybar. Try the glow fuel flush or I use compressed air (about 20-25psi) to blow it out. If it is new there may be some machining filings or a burr in the tube causing a disruption of fuel flow.

As far as large electric models go, there was an article in Fly RC a few months ago that listed the cost for a .60 sized aerobatic A/C with the motor costing around $300 and the batteries (2) costing $375 each. Of course the ESC was another $275 or so. I can fly a LONG time for that much in glow fuel on a .60 sized plane and not have to buy a new charger or worry about my power supply catching fire if handled less than delicatly. Electric HAS come a long way but until costs go down considerably, I'll stick with glow or gas (even cheaper).

Now if they could only make an electric motor sound like a 4-stroke engine....

John VB

Gotta remember that the muffler is a mini tuned pipe. Sometimes when the low speed needle is set too rich the engine can't "get on" the pipe.

I had this happen with a Tower .46 that I put back into service a couple of weeks ago. It started and idled fine but but started to rev up and died when the throttle was opened. This was with the glow battery connected. Since it would start at idle without choking it hadn't gone lean. So I leaned the low speed needle an eighth turn at a time 'til it would rev up, then set the high speed normally. Then I tried the pinch test at ldle. It died right away, so I opened the low speed maybe 1/16th and flew it. It ran out the tank through three flights, so it must be set pretty close. ;^)

You have to remember that the engine runs on the low speed needle up until about 3/4 to 7/8 of the throttle travel.

Cheers,

CR

jeffm wrote: