Question:

I have heard through the rumor mill that people are going to 16 inch headers on the DA170 RE3 combination, is this correct ? I am finishing up a build with a 14 in header set up on RE3's. Am I missing something here or is this all rumors ?

Thanks

I'm not sure about 16-inch header. Compare their numbers with the one I have given for 14", see if its more. It has to be on the same prop. I still have my original plane, DA170 and header all in one piece. Love everything about it.

Thanks that's what I thought, but I wanted to check before I welded the 2 inch extensions on my stock 12 inch headers.

I think you will be happy with 14". When I did this there was no 14" header. After results were shown to be good, MTW made 14" headers.

Originally Posted by Reza

I think you will be happy with 14". When I did this there was no 14" header. After results were shown to be good, MTW made 14" headers.

Yeah when I bought them DA only sold 12" headers and 2" extensions

Hey Reza i cant remember the others, what were the numbers at the other header length you used?

I don't remember ..Been a while and that guy removed the video. RPM increase from 12" was not drastically different, mid range and smoothness was. When I flew the 12" and tached the plane after flight when engine was hot the RPM drop was more than when I did the same with 14", meaning engine was staying cooler throughout the flight. I could feel the pull being much better throughout the flight and performance stayed constant.

Thanks crash and burn
Gives me an idea on thrust
So about 80 pounds or so
Plane weighs 46 pounds
Seems it would do me good to install tuned pipes

Hey how about a 2 blade Break in prop for a 170 on RE3's, any recommendations ? I love the look of a 3 blade but I think i will be to much load. Plane will be about 37 LBS, flying at 600 MSL.

Originally Posted by orthobird

Thanks crash and burn
Gives me an idea on thrust
So about 80 pounds or so
Plane weighs 46 pounds
Seems it would do me good to install tuned pipes

Here is a 37 LBS yak DA 170 on RE3's with a Mejzlik 29X12N 3-Blade

Pilot RC Yak 54 37% DA-170 RE3 Pipes Flown at Jetero Airfield (4 min 20 sec)

I never had break-in and after break-in props so I would not worry about that much, as long as you allow for cooling, loading and unloading the motor properly, you should be good with any prop as long as it is within the DA170 acceptable prop range....

30x12 Mejz, AM 31x12 (loud but awesome IMO), 30x13 EVO (never tried it myself but people like this prop). I like 12 pitch props personally.

Originally Posted by crash-n-burn

Hey how about a 2 blade Break in prop for a 170 on RE3's, any recommendations ? I love the look of a 3 blade but I think i will be to much load. Plane will be about 37 LBS, flying at 600 MSL.

Originally Posted by Reza

I never had break-in and after break-in props so I would not worry about that much, as long as you allow for cooling, loading and unloading the motor properly, you should be good with any prop as long as it is within the DA170 acceptable prop range....

30x12 Mejz, AM 31x12 (loud but awesome IMO), 30x13 EVO (never tried it myself but people like this prop). I like 12 pitch props personally.

+1. No need for a break in prop. I have never used on either. have not tried a 30/12 on a 170 seems kinda light for this engine. But i do like the 31/12 and plan on trying a Mej and Falcon 30/13 to see how i like it.

Originally Posted by jamesrxx951

+1. No need for a break in prop. I have never used on either. have not tried a 30/12 on a 170 seems kinda light for this engine. But i do like the 31/12 and plan on trying a Mej and Falcon 30/13 to see how i like it.

Just another data point, used to use the 30x13EvoL prop on a 170 and RE3's in a 42 lbs. Comparf but the prop ripped at little over 1/2 throttle which was too much for the IMAC unlimited sequence. The 30x13evo non-lightened was even worse! With a K factor of 15, a poor sound score can make all the difference between winning and losing. Looked into the Falcon 30x14 and it is calculated to be 200 rpms slower but with the same thrust. Sure enough it came in at that ~200 rpms less and no less performance on up lines. No more ripping. However, the plane can get a little speedy if you don't watch the throttle.

I have a line on a Cheap Mej 30x12 ( less than $100) , I was just worried it would be to loud / not enough prop. Props are so expensive I am really trying to buy only once LOL. Eventually I will definitely try a 3BL but 2BL is prolly the best way to start.

Originally Posted by nordqk

Just another data point, used to use the 30x13EvoL prop on a 170 and RE3's in a 42 lbs. Comparf but the prop ripped at little over 1/2 throttle which was too much for the IMAC unlimited sequence. The 30x13evo non-lightened was even worse! With a K factor of 15, a poor sound score can make all the difference between winning and losing. Looked into the Falcon 30x14 and it is calculated to be 200 rpms slower but with the same thrust. Sure enough it came in at that ~200 rpms less and no less performance on up lines. No more ripping. However, the plane can get a little speedy if you don't watch the throttle.

Thanks for this information. Have you had a chance to hear or fly with the falcon 30/13? A 14 does sound fast. Not sure if having the H9 3.1m Sukhoi and the big round cowl will help with speed or not.