OS 55AX Head Temp Run **My 900th Video** 

11.100 rpm on an APC I expected more,,,

Like the head temp. Did not suspect the temps to go down so much the faster engine goes.

I just bought one of these and i have a 6 lb Pica Rapier i'm putting it on... trying to decide what prop to put on it?

The sensor may be more accurate if it was placed on the rear of the engine out of direct airflow. It would be interesting to see how over propping or under propping effects head temperature.

So I am nearly convinced to get one to replace my Irvine .53 made in japan with the OS lost it's chrome syndrome,,,

Keep the temp gauge and experiment optimal location for better temp readings. I use the same temp gauge on my Nitro Helicopters. I need to tune and get them into peak performance for consistent power without damaging the engine.

That's pretty interestedly!

Was this engine broken in already for the Temps that you got?

Hi, David, and thank you for the videos, which have been really helpful. With your expertise, could you suggest a 'tickover' rpm for the OS 55ax, please, just a 'ballpark' figure is fine. I will be setting a new one up in the coming week to emplace on a 50's Astro Hogg! Talk about a blast from the past - I gave £30 for it at a show a couple of years ago, and now we're all on lockdown, am finally tackling the job.Take care of yourselves, diolch eto, Den, Cymru (Wales)

Great heat dissipation by the OS 55AX. The head temp did get a maximum of 130 Ceslius degree (199 ºF) after the engine. My old glow Thunder Tiger GP 42 gets 130 ºC (202 ºF) at full throttle in level flight with master airscrew 11x7 prop, trainer airmodel, Wildcat/Byron 15% nitro glow fuel (18% oil), OS Nº8 glow plug at brazilian spring season. Cheers from Brazil! PS. The telemetry temp sensor was placed on the left side of the motorhead too.

Defo include it, David - Your expertise is a valuable asset to the i/c fraternity! Also, BIG PLUS, this one has subtitles, so the third of the world that suffers from hearing loss, including myself, can understand what's going on! Keep safe on the other side of the pond, God bless you all, Den, Cymru (Wales)

Mine is around 130'C in full throttle.. and goes around 90'C idle.. i live in indonesia.. very hot.. I used turnigy temp gun for the measurement. Point at the glow plug.. sry for my bad english.

Hey David. I really believe that its important to have some base line information to go by especially to us who run alot of planes that the engine is in a cowl. I know one time you told me that a majority of your planes were open cowl. The question that i had put fourth to you was not able to be addressed because of that fact. Im really glade that the motor you ran this video with was the os55 because that was the one i had ask the opinion on. I have currently been unable to run mine with the cowl off to really get a good base line due to temps in the 20s. This helps me i believe. My motor is brand new and ive done the run in. Two tanks were treated as breakin tanks even tbought my instructions call for one tank for that proceedure and then fly conservatively. Ive run an additional tank threw it with varying throttle. The one day that i was going to fly it for the first time(before it got cold) it was exhibiting to me what would be a running lean condition and was getting alot warmer than i thought that it should and was unable to make any adjustments. That day i didnt have my temp gun with me. No cowl later at home ran great. I could adjust and tune the motor. At the field in the cowl nadda. So i really appreciate this video. I know that it has helped me if no one else. Thankyou David.

i have had oneof these for years in a funfly pulls 13000 rpm with a13 by 4 prop never lets me down model will hover at half throttle os power

I think the temp readings is a great idea David ,definately keep it ,and congrats on number 900 you are a machine!!

Awesome sensor. But I definitely say u need to lean that midrang some. Later on of course.

Congratulations on your 900th video. I think the temp sensor is a good addition

Congrats on the 900th video. Can't wait to see more...

Awesome video man. Question for you I just received my new OS 55ax and I ran one tank to break in the engine running rich and lean for 10 seconds each. I've been decided to check how many turns the high-speed needle was out from the factory. I found out that from fully closed the high speed needle only turned out one-and-a-half turns from the factory. The manual in everybody online states that two and a half turns is the factory setting how is my engine running with only one-and-a-half turns from fully closed thanks

A nice add to the super imposed tach. I like it.

Ditch it , more interested in look inside engine and carburetor adj. And valve adj.on 4 strokes . Carburetor adj.And proper prop size will take care of cylinder temps. Keep up the good work !

Very informative video David! I think it’s valuable data and would be beneficial on future runs with other fuel percentages/ other motors. Oh.... congrats on your 900th video! All the work you put into these videos is greatly appreciated! 👍🏻😃✌🏻

Engine cowling would surely make a difference in head temp, no air flow, no cooling...

sounded like it was to lean on the low end, Bog down on throttle up.

good video david as always, just one question what's the reason for putting the glow driver back on when the engine is running?

I would suggest to place the temp sensor on the back of the head of the engine so that (the sensor) is not cooled down from the propeller. The placement on the side doesn't give an accurate temperature reading. You can immediately see this at 2:31 when the engine was running and is off, and when you started it again the temperature had a huge drop instantly. Here's a video I made about installing sensors for a Turnigy telemetry radio, which is relevant to this. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-rN3ESW9FXwM.html

Hey David I was breaking in my 55ax yesterday. It maybe had been run once before by the previous owner. It has good compression and it fire right up. It would not open up full throttle without dying until I had ran a couple of tanks through it while working the needle lean and rich as suggested. During the process I notice that the exhaust residue was dark in color with little specs scattered around in it. The motor seems To run fine with good response, the specs kinda concerned me. Is this normal for a new engine?