Dave Gray had an MT on his Potez engined Mascaret some years ago so LAA approval shouldn't be a problem, however the £7K plus price tag might be! Used to be based up at Barton.
I seem to remember there was some kind of rev limit imposed as the blade vibration data had not been tested by the factory. Haven't seen Dave around for a while but I believe he still has the Mascaret, a superb example it is to.
Jodel 1050
Moderators: John Dean, Moderator
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ChristophDommermuth
- Posts: 1
- Joined: Fri Apr 20, 2012 1:30 pm
- Location: germany
I am a DR 1050 owner in germany - engine Conti O 200 A
If anyone have questions regarding that plane - in special with that fantastic motor (100 hp) - don't hesitate to contact me,
regards christoph
regards christoph
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Will Greenwood
- Posts: 147
- Joined: Mon Jan 07, 2008 6:08 pm
- Location: EAST SUSSEX UK
- Contact:
C85 pistons
Not quite that easy, the pistons need to be machined around the top to stop fouling the head, as they have the pin lower in the body than C90/0=200 types.
The other thing is that the compression rise is not that much, but would need them be run on avgas, they would need a reduction in ignition timing to stop knock. I do not think that the power gain would be worth the trouble, it is one of the american power myths. More power really needs more RPM and better volumetric pressure. There are higher compression pistons available but cost and arm and leg. Plus try getting them through engineering might be problematic.
Allowing an 0-200 to run at the correct timing would put the power back to where it should be and not lower than a C90 as they are, unless you have changed the barrels from ones that are fitted originally, to types that don't crack around the joint??? This is seems to be forgotten by a lot of people who still think the AD applies to 0-200 s regardless. It only applies to the cracking type.
Graham
The other thing is that the compression rise is not that much, but would need them be run on avgas, they would need a reduction in ignition timing to stop knock. I do not think that the power gain would be worth the trouble, it is one of the american power myths. More power really needs more RPM and better volumetric pressure. There are higher compression pistons available but cost and arm and leg. Plus try getting them through engineering might be problematic.
Allowing an 0-200 to run at the correct timing would put the power back to where it should be and not lower than a C90 as they are, unless you have changed the barrels from ones that are fitted originally, to types that don't crack around the joint??? This is seems to be forgotten by a lot of people who still think the AD applies to 0-200 s regardless. It only applies to the cracking type.
Graham
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Brian Hope
- Posts: 1271
- Joined: Tue Jan 08, 2008 8:28 pm
- Location: Sheerness Kent
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Nigel Hitchman
- Posts: 357
- Joined: Thu Jan 03, 2008 5:10 pm
- Location: Hinton in the hedges
I dont know about this mod, but "Dons Dream machines" builds C85s with O-200 crankshafts and maybe a few other changes, these are reported to give over 100hp and also be a cheaper rebuild than finding new C-85 parts. There are in Griffin,Georgia. A friend operates a couple of Cubs with this engine in his flying school and is very happy with them. Not sure if there are any in the UK though.
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Graham Clark
- Posts: 64
- Joined: Tue Dec 09, 2008 6:28 am
Retro-Fit
Slightly tongue in cheek: a well sorted Potez 4E20 delivers 105 hp and is almost a 'plug and play ' substitute for an O-200. Fitted with mags in lieu of the old distributor, it is a new engine. I have one in my DR1051M1, which is very slightly smaller than the DR220, and serves me very well.
I can hear the sneers already from Kent, but at the price I didn't pay, I can afford to feel smug.
I can hear the sneers already from Kent, but at the price I didn't pay, I can afford to feel smug.
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Steve Brown
- Posts: 257
- Joined: Wed Jan 02, 2008 11:00 am
Hi - yes, I did a formal LAA mod on my O-200 to use C85 pistons and wrote an article in the mag a couple of years back. Brian may be able to help on the exact issue.
I did a lot of research on this, including contacting TCM directly. There is a lot of rumour and extravagant claims on this mod which I think I can dispel.
It raises compression ratio from 7.0 :1 to between 8.0 and 8.2:1 (no more, no less) so UL91/Mogas is possibly technically still a feasible option (cut off point is approx around 8.5:1) but LAA Engineering would be final arbiter on that.
Power / efficiency increase is about 5-6% on a like for like (ie at same rpm) basis ie around 105-106HP.
Note the new TCM O-200D has finally caught up and now has a compression ratio of 8.5:1 which requires 100LL according to its type certificate. Minimum power is still 100HP though!
We are using the more recent (641917 and onwards) cylinders (that don't crack and can accept the original 28 deg BTDC timing. Ignition timing was retarded 4 deg to account for the more efficient combustion chamber flame burn.
Was it worth it ? - a resounding yes. What was immensely valuable to me was (using the same otherwise perfect prop) that the static rpm rose from 2220rpm (53% of 100HP) to 2400 rpm (65% of 105HP) ie an approximate 25% increase in take off power - and that sure is noticable!
In the cruise at like for like TAS, the extra efficiency reduced fuel consumption by around 5-6%.
I did a lot of research on this, including contacting TCM directly. There is a lot of rumour and extravagant claims on this mod which I think I can dispel.
It raises compression ratio from 7.0 :1 to between 8.0 and 8.2:1 (no more, no less) so UL91/Mogas is possibly technically still a feasible option (cut off point is approx around 8.5:1) but LAA Engineering would be final arbiter on that.
Power / efficiency increase is about 5-6% on a like for like (ie at same rpm) basis ie around 105-106HP.
Note the new TCM O-200D has finally caught up and now has a compression ratio of 8.5:1 which requires 100LL according to its type certificate. Minimum power is still 100HP though!
We are using the more recent (641917 and onwards) cylinders (that don't crack and can accept the original 28 deg BTDC timing. Ignition timing was retarded 4 deg to account for the more efficient combustion chamber flame burn.
Was it worth it ? - a resounding yes. What was immensely valuable to me was (using the same otherwise perfect prop) that the static rpm rose from 2220rpm (53% of 100HP) to 2400 rpm (65% of 105HP) ie an approximate 25% increase in take off power - and that sure is noticable!
In the cruise at like for like TAS, the extra efficiency reduced fuel consumption by around 5-6%.