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max RPM on 503 drifters


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Can I please get some info from other drifter pilots and even others who fly a 503 powered aircraft. I am not happy with the climb performance of my plane. I went for a spin in another 503 powered drifter and it really out-performed mine.


The first thing I am wondering is what the maximum RPM reached on takeoff and climbout is on other aircraft. Mine is up at 6800 rpm which is the far limit on the perfromance graphs and from what I can work out, past the best torque or power areas. The drifter manual from the 80's lists 6250 rpm as the max.


Any help would be greatly appreciated.



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rotax 503 rpm


if you are getting 6800 rpm its reving prety hot and you should'nt have any climbing dificulties but there is a possibility that your tacho might be incorrect. it happened to my 503 few years back and the tacho was showing 7200 rpm and when checked with another tacho it was doing 6250 rpm. for getting the maximum torque and in the interest of longivity of engine life aim for 6400-6500 max.


also the one you went for a spin was it similar to your drifter, original maxair drifters and wayne's fisher models climb much better than certified drifters (which can be a real dog on a hot day with two on board)





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The plane I flew in was actually waynes trainer but an austflight drifter (25 rego for training)


I will be ordering a tiny tach in a week or so after I measure up the length of lead required. This should give me an acurate RPM and maybe I can reconsider from there. I am generally cruising around 50kts at 5600 rpm one up in calm conditions. 2 up on the same nice day was 5800-6000 rpm.



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Guest stan ----avalon

hi there compadre meaning (friend) it all comes to your prop pitch increase pitch till you revs cant go past


62800rpm and check your jet-needles for hight(connection)3rd from the bottom up and you re screaming up wards all so check you sparkis must be brownish at the electrode and little oily blackish round the rim?- if whitish electrode appears it means carb is too lean so go back to connection two from bottom it should be ok happy flaying



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hahaha no worries I knew what you ment! Thanks for the advice :thumb_up:.


Changing the pitch of the prop was what I was thinking but I will take earlier advice first and install a tiny tach to get an acurate reading. If this confirms that I am climbing out at 6800 rpm I start looking into changing the pitch.


The plugs look good and are only slightly brown with no melt spots or excessive gunk at 25hrs.



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