Hi all and seasons greetings,
I'm not a home builder but enjoy this forum as there are lots of very interesting discussions with very knowledgeable owners,
I have a UK registered trike with a DCDI 503 fan cooled with a 3 blade Warp Drive pusher...bought the 503 motor for it new last summer...one of the last available in the UK,
Anyway I bought one of those budget Tiny Tach type tachos a few weeks ago from China....at around $15 nothing to loose and may come in handy for testing,
Anyway I thought I would test it for accuracy thinking that my engine was set up fine RPM wise...I had set my 503 originally at 6250 static which is supposed to give 6500rpm max at take off,
I was quite surprised that the tiny tach indicates the the a/c tach is reading 150rpm low...I was under the impression that the a/c tach was over reading by about 5% after setting it with a hand-held laser tach....the a/c tach is one of those small Westach analogue type....
I tested it with the laser tach at the same time and it agrees with the Tiny tach copy...if fact I ran a side by side test on my wifes car and both gauges are within 10rpm of each other....must say its easier to do an RPM test on the car that the a/c,
What bothers me now is that the a/c tach reads around 6900rpm take off which could be near 7100 if the tiny tach is right....I was under the impression it was really giving 6500rpm,
Had a look in the Rotax manual last night to refresh my memory and it quotes 6800rpm take off max 5 mins....but every body I ever speak to says set my engine to 6500rpm take off which is around 6250 staic in my case,
So my question...do I set it to give 6800 on take off...or 6500rpm,
My cruise RPM is 5000rpm indicated on the a/c tach....my trike flys at more or less a constant speed unlike a fixed wing type a/c.
Nick.
I'm not a home builder but enjoy this forum as there are lots of very interesting discussions with very knowledgeable owners,
I have a UK registered trike with a DCDI 503 fan cooled with a 3 blade Warp Drive pusher...bought the 503 motor for it new last summer...one of the last available in the UK,
Anyway I bought one of those budget Tiny Tach type tachos a few weeks ago from China....at around $15 nothing to loose and may come in handy for testing,
Anyway I thought I would test it for accuracy thinking that my engine was set up fine RPM wise...I had set my 503 originally at 6250 static which is supposed to give 6500rpm max at take off,
I was quite surprised that the tiny tach indicates the the a/c tach is reading 150rpm low...I was under the impression that the a/c tach was over reading by about 5% after setting it with a hand-held laser tach....the a/c tach is one of those small Westach analogue type....
I tested it with the laser tach at the same time and it agrees with the Tiny tach copy...if fact I ran a side by side test on my wifes car and both gauges are within 10rpm of each other....must say its easier to do an RPM test on the car that the a/c,
What bothers me now is that the a/c tach reads around 6900rpm take off which could be near 7100 if the tiny tach is right....I was under the impression it was really giving 6500rpm,
Had a look in the Rotax manual last night to refresh my memory and it quotes 6800rpm take off max 5 mins....but every body I ever speak to says set my engine to 6500rpm take off which is around 6250 staic in my case,
So my question...do I set it to give 6800 on take off...or 6500rpm,
My cruise RPM is 5000rpm indicated on the a/c tach....my trike flys at more or less a constant speed unlike a fixed wing type a/c.
Nick.
Last edited:
