Hi all,

I have completed my Inital test on my 2 OS 61V Engines

I need to decide which of my two engines and carb /Pump setup I am going to use to power the arrow before I start sanding the engine bay.

My main goal is to work out which is going to be the most relable, and I am a curious person :- I like to work things out for my self much better than a blind guess.

This is what I will be testing

OS 61 V Which I am going to call "Engine A " :- Low usage engine came fitted with 7M carb only no pump, bought in box with Manual only damage small scrape on one fin nothing to fuss about.

OS 61 V Which I am going to call "Engine F"(Frankinstien):-It was bought "AS-IS" for its OS pump and 7D carb condition unknown, it has had a hard life crashed at some stage lost a Whole fin on the head and the pipe mount area was welded back onto the casting and machined flat new holes were tapped to take longer Non Metric Bolts. The piston and linner are NONStandard and have had a radical porting job how good a job we will soon see.


Both Engines were run on a Standard fuel of 20% Castor, 5%Nitro Same pipe / same Glow plug same Props Even same prop nut.

RPM by a Hanger 9 Tacho from behind the prop.


Results
______



Engine A Pipe presure only 7M carb

1332 RPM Bolly 11.5 x 7
1050 RPM Graupner 12.5x6

Engine A with OS Pump and 7D

1340 RPM Bolly 11.5 /7
1080 RPM Graupner 12.5 x6


Engine A:-Idle's nice and is happy with the 7M and Pipe Pressure Only, Very good safe choice for the Arrow


Engine F Pipe presure only7M carb

13730RPM Bolly 11.5 x7
11880RPM Graupner 12.5 x 6


This engine is Nutts !!! it sounds like hot Rotory Engine when it Idles !!! who ever ported this one Knew what they were doing !!!

Engine F OS Pump and 7D

14020 RPM Bolly 11.5 x7
12150 RPM Graupner 12.5 x 6

The two Photos are "Frankie" Engine F on test

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