Engine RPM question - Zenith Aircraft Builders and Flyers2024-03-28T17:06:20Zhttps://zenith.aero/forum/topics/engine-rpm-question?commentId=2606393%3AComment%3A675011&feed=yes&xn_auth=noHello Ken...
Some folks won't…tag:zenith.aero,2019-04-27:2606393:Comment:6751312019-04-27T22:42:05.929ZR Michael Moorehttps://zenith.aero/profile/RMichaelMoore
<p>Hello Ken...</p>
<p>Some folks won't eat yogurt no matter how much evidence they are presented with. Ask me about Brussels Sprouts. Yuck. Engine choices are somewhat like that. </p>
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<p>Air cooled aircraft engines as with auto engine conversions to aircraft use are all based on 116 year old design features.</p>
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<p>What has changed over more than a century?? Here is a great article from FLYING magazine. …</p>
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<p>Hello Ken...</p>
<p>Some folks won't eat yogurt no matter how much evidence they are presented with. Ask me about Brussels Sprouts. Yuck. Engine choices are somewhat like that. </p>
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<p>Air cooled aircraft engines as with auto engine conversions to aircraft use are all based on 116 year old design features.</p>
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<p>What has changed over more than a century?? Here is a great article from FLYING magazine. </p>
<p><a rel="nofollow" href="https://www.flyingmag.com/aircraft/pistons/piston-engine-technology">https://www.flyingmag.com/aircraft/pistons/piston-engine-technology</a></p>
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<p>Really I think budget should be the major deciding factor. If a Rotax is in your budget go for it but I would say get the fuel injected version. My previous airplane had the HKS 700E with those same dual Bing carburetors. If you like the standard Rotax and those Bings -- have a good and experienced Rotax A&P. Enough said. Why then Rotax over UL Power or Jabiru? All three are equally well proven designs.</p>
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<p>Those that raise the glower of doom and loss of life and limb saying auto conversions are a safety risk are simply not dealing with facts. BUT there is serious cause for caution.</p>
<p>Here are four articles that cover the topic very well. </p>
<p>-1-</p>
<p><a rel="nofollow" href="https://generalaviationnews.com/2018/10/11/homebuilt-accident-rate-drops-to-new-low/">https://generalaviationnews.com/2018/10/11/homebuilt-accident-rate-...</a></p>
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<p><a rel="nofollow" href="http://flash.avweb.com/avwebflash/news/Experimental-Accident-Rate-Lowest-Ever-231648-1.html">http://flash.avweb.com/avwebflash/news/Experimental-Accident-Rate-L...</a></p>
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<p><a rel="nofollow" href="http://www.dviaviation.com/experimental-aircraft.html">http://www.dviaviation.com/experimental-aircraft.html</a></p>
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<p><a rel="nofollow" href="https://airfactsjournal.com/2017/10/whats-wrong-experimental-pilots/">https://airfactsjournal.com/2017/10/whats-wrong-experimental-pilots/</a></p>
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<p>Powerplant failures in E-AB aircraft are a serious problem and all too often in the early phase of testing. But the problem is NOT the engine. It is the installation and that rests solely with the builder in the E-AB world. </p>
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<p>Installation means fuel, air, and electricity need to be done right. </p>
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<p>The EAA now recommends comprehensive on the ground testing of those systems before first flight. </p>
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<p>Kudos to those brave test pilots who will then step up and into our E-AB's for the crucial leap into real flight.</p>
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<p></p> "Thats why I asked this when…tag:zenith.aero,2019-04-27:2606393:Comment:6751992019-04-27T14:13:16.760ZKen Ryanhttps://zenith.aero/profile/KenRyan
<p><span>"Thats why I asked this when many people say stay away from engines that are not developed for aircrafts." -- Many people have minds that are closed to new ideas. These people would never condone using an engine out of an automobile, no matter how much evidence they are presented with.</span></p>
<p><span>"Thats why I asked this when many people say stay away from engines that are not developed for aircrafts." -- Many people have minds that are closed to new ideas. These people would never condone using an engine out of an automobile, no matter how much evidence they are presented with.</span></p> Yes I agree to this, This is…tag:zenith.aero,2019-04-27:2606393:Comment:6750112019-04-27T13:06:44.758ZJonas Öhlinhttps://zenith.aero/profile/JonasOEhlin
<p>Yes I agree to this, This is what I think also. It all about how you maintain and operate the engine. </p>
<p>Of course there may be less maintenance on a factory built aircraft engine.</p>
<p>Thats why I asked this when many people say stay away from engines that are not developed for aircrafts.</p>
<p>I will probably go with the Rotax in the end most because I think it´s the easiest engine to buy here. But all the engines discussed here are interesting.</p>
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<p>Thanks.</p>
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<p>Yes I agree to this, This is what I think also. It all about how you maintain and operate the engine. </p>
<p>Of course there may be less maintenance on a factory built aircraft engine.</p>
<p>Thats why I asked this when many people say stay away from engines that are not developed for aircrafts.</p>
<p>I will probably go with the Rotax in the end most because I think it´s the easiest engine to buy here. But all the engines discussed here are interesting.</p>
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<p>Thanks.</p>
<p></p> Hi Jonas..
Thinking those are…tag:zenith.aero,2019-04-27:2606393:Comment:6751942019-04-27T11:53:51.368ZR Michael Moorehttps://zenith.aero/profile/RMichaelMoore
<p>Hi Jonas..</p>
<p>Thinking those are math / engineering numbers that are not easily available. Maybe someone here can give more specifics. But I am not sure how this helps.</p>
<p>What we are familiar with is the TBO. You saw in the video on V8 auto conversion that, because he races with the faster engine, valve jobs are frequent. But not an overhaul of the engine. "No appreciable wear." So for most auto conversions there are no fixed TBO figures given. Think years and years. …</p>
<p>Hi Jonas..</p>
<p>Thinking those are math / engineering numbers that are not easily available. Maybe someone here can give more specifics. But I am not sure how this helps.</p>
<p>What we are familiar with is the TBO. You saw in the video on V8 auto conversion that, because he races with the faster engine, valve jobs are frequent. But not an overhaul of the engine. "No appreciable wear." So for most auto conversions there are no fixed TBO figures given. Think years and years. Rotax has a published TBO. </p>
<p>So really the answer to your question rests with how you operate and maintain the engine. That makes all the difference. Even the best engine can be run into early failure by a poor operator and bad maintenance. </p>
<p>We are fortunate to have lots of good engine choices now including auto conversions at less than half the price of a Rotax. This forum discusses eight different engines. All are well proven, safe and reliable or they would not be here. Up to you.</p> Thanks for all the info, have…tag:zenith.aero,2019-04-27:2606393:Comment:6750072019-04-27T10:23:02.836ZJonas Öhlinhttps://zenith.aero/profile/JonasOEhlin
<p>Thanks for all the info, have not read all but I think it answers some questions.</p>
<p>I understand that higher RPM means more stress to the engine but what I meant with my original question was if an engine is designed for a car then driving it on top gear on the motorway at about 2500-3000 RPM is not a problem, even hour after hour. So that same engine in an airplane when double the RPM, how much more stress is it? is it double or is even four times higher?</p>
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<p>I think the…</p>
<p>Thanks for all the info, have not read all but I think it answers some questions.</p>
<p>I understand that higher RPM means more stress to the engine but what I meant with my original question was if an engine is designed for a car then driving it on top gear on the motorway at about 2500-3000 RPM is not a problem, even hour after hour. So that same engine in an airplane when double the RPM, how much more stress is it? is it double or is even four times higher?</p>
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<p>I think the Rotax 912 is the best options but I like to think outside the box. But not so much that I´m willing to risk my life :).</p>
<p>I see now even snowmobile and motorcycle engines are used in airplanes and those engines have even higher RPM.</p> Our test flight numbers show…tag:zenith.aero,2019-04-27:2606393:Comment:6750022019-04-27T03:47:15.832ZLoren Warnerhttps://zenith.aero/profile/LorenWarner
<p>Our test flight numbers show a comfortable 50 KIAS at 3710 rpm (2.4 gph) and 60 KIAS at 3966 rpm (2.6 gph). Being that this aircraft is built for STOL, it's prop is pitched for a max 5400 rpm during climb-out, and we never intend to exceed 5400 rpm during level flight. Our rpm at 70 KIAS is 4380 rpm (3.6 gph). This aircraft will easily climb at much lower rpm, and as you can see will not likely be operated above 4500 rpm during level flight. …</p>
<p>Our test flight numbers show a comfortable 50 KIAS at 3710 rpm (2.4 gph) and 60 KIAS at 3966 rpm (2.6 gph). Being that this aircraft is built for STOL, it's prop is pitched for a max 5400 rpm during climb-out, and we never intend to exceed 5400 rpm during level flight. Our rpm at 70 KIAS is 4380 rpm (3.6 gph). This aircraft will easily climb at much lower rpm, and as you can see will not likely be operated above 4500 rpm during level flight. <a rel="nofollow noopener" href="https://l.facebook.com/l.php?u=https%3A%2F%2Fdocs.google.com%2Fspreadsheets%2Fd%2F1dvpnekIIWBNePgzYAGNqe6kLI823CcKjsV_ezXSfTuc%2Fedit%3Fusp%3Dsharing%26fbclid%3DIwAR2vcML3ZsWQfGwazQ4Zy_lw_lWf4CvemBEBe2NtzYu9T_vIjXz-HWeqmQw&h=AT3gsGmtbvzQqMQhQfVzW0s_OWtAI1UpMJc-aBYuLsVw7jPN0ZNHVSO7Qym_5l2xFJMSxgesS1mqjyahuGZGBaTOE7sY9v3Bea1xGqLKa13PdsswpkWSe-SxwhOrTVzFDdfVCuM" target="_blank">https://l.facebook.com/l.php?u=https%3A%2F%2Fdocs.google.com%2Fspre...</a></p> Trying to not hijack the orig…tag:zenith.aero,2019-04-27:2606393:Comment:6748812019-04-27T03:41:09.933ZR Michael Moorehttps://zenith.aero/profile/RMichaelMoore
<p>Trying to not hijack the original thread, but should mention the Viking 90, a Mitsubishi 3 cyl auto conversion, is on an SP-30 in Deland FL. Although, I did not clarify with Deane, that is probably the aircraft that he flew with the Viking 90. The SP-30 is a CH-701 derivative produced in Russia and used extensively for Agricultural spray work. </p>
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<p>I saw Samuel's data page on climb rates and power settings etc. Good stuff.</p>
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<p>Happy flying. Hope we have been…</p>
<p>Trying to not hijack the original thread, but should mention the Viking 90, a Mitsubishi 3 cyl auto conversion, is on an SP-30 in Deland FL. Although, I did not clarify with Deane, that is probably the aircraft that he flew with the Viking 90. The SP-30 is a CH-701 derivative produced in Russia and used extensively for Agricultural spray work. </p>
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<p>I saw Samuel's data page on climb rates and power settings etc. Good stuff.</p>
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<p>Happy flying. Hope we have been helpful to Jonas with his original question. </p> Hello Michael. How is our fa…tag:zenith.aero,2019-04-27:2606393:Comment:6751082019-04-27T01:04:34.284ZLoren Warnerhttps://zenith.aero/profile/LorenWarner
<p>Hello Michael. How is our far east buddy doing these days? Spring has finally arrived for us here in Anchorage, although we're still likely to see a little snow up through mid-May. <br></br><br></br> I didn't recall that Deane had also flown the 701 with the Viking 90. Unless into extreme STOL, seems to me the 701 would probably be best with the Rotax 912 or Viking 90. <br></br><br></br>Samuel is still working on Phase 1 and very much enjoys flying the 750 STOL with the Viking 130. Our builders page…</p>
<p>Hello Michael. How is our far east buddy doing these days? Spring has finally arrived for us here in Anchorage, although we're still likely to see a little snow up through mid-May. <br/><br/> I didn't recall that Deane had also flown the 701 with the Viking 90. Unless into extreme STOL, seems to me the 701 would probably be best with the Rotax 912 or Viking 90. <br/><br/>Samuel is still working on Phase 1 and very much enjoys flying the 750 STOL with the Viking 130. Our builders page has numerous Utube showing take-off, landings, climbing, and stalls. He's been collecting lots of data, but has not done any short take-off or landings. His typical take-offs have been around 200 ft.</p> Hello Loren..
Since this thre…tag:zenith.aero,2019-04-27:2606393:Comment:6749952019-04-27T00:44:14.414ZR Michael Moorehttps://zenith.aero/profile/RMichaelMoore
<p>Hello Loren..</p>
<p>Since this thread is all about Auto Conversions and how they apply, here is a bit of info. I just had a very good conversation with Deane Philip who owns a CH-701 in New Zealand. A few years back, Deane installed the Viking 130 HP with 20 lbs of lead in the tail. Serious STOL operator. 50 feet for take off Deane said is easy !!</p>
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<p>Deane has flown the Viking 90 and had only positive comments - only saying it is louder. His mission is all about STOL…</p>
<p>Hello Loren..</p>
<p>Since this thread is all about Auto Conversions and how they apply, here is a bit of info. I just had a very good conversation with Deane Philip who owns a CH-701 in New Zealand. A few years back, Deane installed the Viking 130 HP with 20 lbs of lead in the tail. Serious STOL operator. 50 feet for take off Deane said is easy !!</p>
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<p>Deane has flown the Viking 90 and had only positive comments - only saying it is louder. His mission is all about STOL and reliability in rough terrain. Hence the Viking 130. So we see proof proper of the comment I made just earlier about weight vs Horsepower. </p>
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<p>How is the Alaska spring looking for your CH750? Or does spring come in May for you? LOL. </p> While the Rotax 912 is popula…tag:zenith.aero,2019-04-26:2606393:Comment:6749892019-04-26T23:27:56.635ZLoren Warnerhttps://zenith.aero/profile/LorenWarner
<p>While the Rotax 912 is popular in the Zenith 701, Viking's 90 seems like a good alternative. </p>
<p>While the Rotax 912 is popular in the Zenith 701, Viking's 90 seems like a good alternative. </p>