skillet92

Hey guys, it is me again. I have a Ralph converted G-38 and just need some advise before I fly this beast. I have a ESM corsair plane is balanced and weighted. 18lbs 11ozs. I am getting 15 pounds of thrust on an 18x8 MA wood yellow tipped prop. Would a different prop or bigger prop give me more? And I guess this is the question that I am wondering do I need more? I do not know the RPM exactly. I have learned that sometimes more RPM is not better! So I look at the thrust number more than the RPM. I have room for a bigger prop! Just wanted some info before I go and buy some. Thanks

PS this has got to be the smoothest running and easiest starting engine that I have. The only other issue that I have to figure out is that it loses rpms when I go to full throttle but if I back off a couple of clicks the rpms pick up. I do have a Velocity stack on it because the fuel was spitting out so much. It was doing the rpm thing before I put the velocity stack on it and I have adjusted it but it still wants to lose rpms unless I back off the stick. That is not a bigg deal because I can adjust for it in the transmitter I am just curious why??

The Ghost

I am using an 18x10 MA on the same engine, model only weighs 12lb thow.

Sounds like its still a little lean on the top end.

Cheers

Tired Old Man

My Feedback: (1)

Most warbirds are a little heavy unless ultra care is taken during the construction material selection process. Most warbirds have an airfoil design that, combined with the aircraft weight, needs some speed to generate effective amounts of lift. Unless you're flying a trainer or 3d the power to weight ratio is typically even or upside down. Even worse for full scale aircraft. Go with a 10 pitch prop, maybe even a 12, and fly scale, meaning that energy management has to be practiced to some extent.

AA5BY

I have a G-23 that will also lose rpm at full throw. The reason is a previous owner removed the throttle stop and load spring on the butterfly shaft, which allows the butterfly to over rotate slightly.

Tired Old Man

My Feedback: (1)

So it passes "full throw". Full throw does not relate to throttle servo movement, but throttle area fraction. Full throw would equal "1", while anything less or more would be a positive or negative fraction of 1.

the Wasp

My Feedback: (1)

my stock G38 with Mag tuned a 3W 19x8 at 7000 tuned for flight, and peaked at 7200, yet a Zingger 19X8 Pro should turned up 400 more RPM than the 3W Prop,, those 3W Props are Air Biting Props man,

because of the Advancing Timing these Electronic Ignitions have, I have noticed on my friends converted Zenoahs~ yours too should have more power than stock with the Mag..

Jim

skillet92

Just a quick update on the rpms backing off when the stick went all the way forward. I guess in my building of it I set the throw for the carb all the way forward for full throttle and all the way back for closed throttle. I just looked in the carb as I moved the stick and the butterfly goes over center. Not a lot but I guess enough to effect the airflow! I have not run it yet so I will tell ya when I do it this was the problem!