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I recently received my plans for an air bike tandem. I plan on scratch building but this is my first endeavor. I would love to connect with people that have experience with them, or building in general. I’ll be registering it experimental. I’m in North San Diego county. Anyone local. I plan to head down to Brown field next Sat for EAA breakfast, hoping to connect with someone.
Carl
I have not built an air bike but I am finishing up a Zenith 701 and previously built and still fly a Pulsar XP out of Big Bear airport. Am always open for visitors.
Bob H
I have a single-place Air Bike that I'm flying out of Ramona Airport. I'd be happy to show you the aircraft and help you any way I can.
David
Hey Carl-
Congratulations on the Air Bike choice! Me, too! I got my plans late spring and have been getting ready ever since. I am building a single seater, also as experimental. I live in Hollywood and my home field is at Whiteman. We are not "local" enough as I would want, but I would like to come and see your progress and compare notes, as things move along.
Dan
medicalgasdan@gmail.com
I have also kicked around the idea of going "ultralight". But I have heard conflicting reports regarding the reliability of 2-stroke aircraft engines. I would like to get your opinion also, especially regarding the Hirth engines.Quote:
Originally Posted by DAB677
The 2 stroke reputation is from and earlier time when experimentation was without data.That Data gathered from all the bad experience and good , has its roots in today's engines and range of performance. I respect the past and would use the tried and rated . I have been flying with one of the lightest weight to power ratios a 440 Kawasaki . there are many of them out there still in use. If I were going to fly and use a new engine it would be the new F33 Hirth 50 HP electric start and the total weight is only a few lbs over my hand pull Kawasaki system.
There are very few Ultra light engine failures these days. The news is far more disturbing for GA and LSA engine failure , This year has me wondering why.
Thanks, Norm. I have considerable experience with (older) 2-stroke motorcycle engines (Suzuki and Kawasaki), and was perplexed by anecdotes of seizures and in-flight failures of those designed for aircraft. It's nice to hear from someone with actual experience.
Your comment made me curious, Norm: HAS two-stroke reliability increased with time?Quote:
Originally Posted by Norman Langlois
One way to look at the issue is to examine the accidents involving homebuilt aircraft with two-stroke engines, and determine what percentage of the accidents were due to engine issue.
I split my database into two groups: 1998 through 2006 (nine years), and 2007 through 2016 (ten years). The slight difference in number of years doesn't make a difference, since we're look at the percentages rather than the raw numbers.
During the earlier period, 31.6% of accidents involving EAB aircraft with two-stroke engines were due to engine issues.
During the later period, that dropped to 21.4%! So, indeed, the homebuilt world got better at producing reliable two-stroke engine installations.
Here's the figures for several engine classes.
"Non Cert Four Strokes" are engines like the Rotax 912 and the Jabiru. The Rotax 912 itself, in fact, dropped from 15% in the first period to 10% in the more-recent period...better than traditional engines, in fact.
Traditional Engines Auto Engines Non-Cert Four Strokes Two-Strokes
Ron Wanttaja
Ron,Quote:
Originally Posted by rwanttaja
How granular is that data, can you give a breakdown by engine? (I'm particularly curious about the Rotax 582, Rotax 503 and the HKS 700e)
It really depends on the thoroughness and accuracy of the NTSB reports. Often the engine just states "Rotax" with no model number; I don't count these on either the two-stroke or the non-certified four-stroke categories. My full database (1998-2016) shows 456 accidents involving aircraft with two-stroke engines (out of about 3800). The last ten years show only 168. These *are* just EAB-registered aircraft; I don't track Part 103 accidents.Quote:
Originally Posted by thisadviceisworthles
For the full 19-year period, 106 EAB accidents had Rotax 503 variants, and 214 had Rotax 582. 21% of the 503 accidents were due to power issue, vs. 33% of the Rotax 582 cases. There are only four cases involving EAB aircraft with HKS engines. The power system wasn't cited in any of these, but that's just too low of a sample set. According to the FAA database as of a year ago, there were 198 aircraft registered with HKS engines. There were 13,508 listed as having Rotax engines. 1861 were listed as having 503s, 3226 as 582s, but the FAA registry lists just a bunch of generic "Rotax" or "Bombardier" engines with no model number.
Ron Wanttaja
All good info. What I meant to say was, 2-stroke motorcycle engines were (are) virtually bomb-proof. Very reliable, and easy to service and maintain. The drawback: super polluters!
Some consideration of engine choices should include safe landing risk if engine stops. I fly in San Bernardino mountains out of Big Bear where there is no place to put down if engine fails.
If you fly around flat farm fields with plenty of open spaces, survival risk may be higher. But if you routinely fly in rough terrain where put down means a non-survival crash, you want an engine with high reliability and
cost is secondary. I fly a Pulsar with a 912 with 1170 hrs and no engine issues...yet.
I did not base my comment on statistics . On the observed only. and plain logic . The ultra light era gave many individuals opportunities to create . The fly. Your own data shows a decline in incident. Sudden stoppage always has a root . Most will lead to a user error. water ,over rev, improper oil, poor maintenance. Its not the 2 stroke its that 2 strokes need a strict user guideline. That beginning era was indeed experimental with many failures. The answer is obvious ly Yes there are more reliable than before. But still no more reliable than in comparison to 4 stroke. Nether power plant is any better with poor human interaction. If one engine design has been improved to the point it is bullet poof only then would you lift your condemnation of 2 strokes. And that will take another 10 years of statistics and only if all aircraft going forward with 2 strokes are of that design. I do not expect to change your mind if you have a condemnation of 2 stroke use . If you feed your 4 stroke water and let the sump go dry it will stop also.
I agree with Norman. These engines are great for the small aircraft we fly (less expensive, light weight, use of auto fuel, etc.) but they do have operational limitations and they must be maintained and inspected in accordance with the published procedures. I have had two engine-out events and both have been caused by something that could have been corrected had the proper attention been paid to proper procedures. I have almost 50 hours on my Air Bike since its first flight with no unexplained problems and I feel confident that this 447 Rotax will continue to perform reliable fashion ( of course, I still have that landing site picked out all through the flight, just in case...).
It is my experience (and the experience of many others) that a primary difference in reliability between two and four stroke engines is their failure modes. The engine failures I had with two-strokes resulted in sudden stoppage of the fan with no warning. Four strokes are more likely to fail gracefully, usually with ample warning that they are not feeling well if the pilot is paying attention. Two strokes generally operate on the margins of reliability in order to achieve high output with light weight, four strokes often are less stressed for a given percentage of power.....but heavier.
Here is a simple question: Which engine would you prefer to fly at night over hostile terrain......two stroke or four stroke? :)
Turbine. :)Quote:
Originally Posted by Sam Buchanan
Personally, my experience with 2-stroke engines has been limited to R/C engines, a very early 1970s Lawn Boy mower, a '55 Vespa scooter, and a few weed whackers. I think that probably holds true for a lot of people, and trying to mentally translate that experience into something to fly behind (or in front of) can be a challenge. Although, now that I think of it, all of those examples have been extremely reliable as long as they get good gas, enough (but not too much) oil, and the carbs and reed valves don't gum up. When that's happened I don't think I've ever gotten one to run again. Of course that's a perfect example of what happens when someone tries to "fix" something they know next to nothing about.
My original comment was for HAPPYDAN .In considering going Ultralight with his plane. The 2 cycle engines that are being produced for use in aircraft are improved. Liability has made this happen. One can still build and fly a 103 with any engine they choose. But that wont be true for certified. That will require a few more hoops to jump through.
I was at Oshkosh and Sun and fun this year. I stopped by the Hirth booth. I was impressed by the specs for the Hirth F33. This engine was not doing well when first introduced, but has now become one of there top sellers. EXPENSIVE for a 2 stroke option yes. If it is as reliable as projected ,the cost would be worth it. I'm not trying to sell there product.
The one statement made to me, was in answer to my Question how long at full throttle. The reply, was till you run out of gas. That reflects a very reliable mechanical sound engine design. Something to consider about the past use of 2 cycle engines. In an experimental application, engine loading ! The back yard builder would need help with this, but did they in the past 30 yrs. I suggest that over the last 15 yrs we have better recommended prop to engine data. The loading is as important as the fuel mixture . The data that has been gathered has made the choice more reasonable.
Hi Carl,
I am building a Tandem Airbike in Auckland NZ. I have been following the Question Gravity build log http://www.questiongravity.com/airbike/ it is very helpful.
Thanks
Attachment 7787
Who currently sells plans for the Airbike, single and two seat variants?
BTW, I have a 447 powered Airbike (single seat) with 375 hrs. TTAE.
One engine out caused by the pilot (me) doing a steep pull-up which
resulted in the float cutting off fuel to the carb.
Landed safely, pulled re-start and went back to flying.
Attachment 8010
http://www.jordanlakeaero.com/Quote:
Originally Posted by Ronald Franck
That's a sharp Airbike Ronald!
Thanks Clint. Nice looking airframe! Still progressing on the build? I still haven’t started my build, I don’t want to start until I find someone to build in parallel, or help. I am planning on practicing my welding on thin chromoly. Care to share your weld procedure. Are you preheating at all? Back purging inside of tube? What filler er-70s-2 or er-80s-D2? Sizes?
https://www.facebook.com/groups/1369...553/?ref=share
I created a Facebook group for the AirBike since I couldn’t find one. I’m sure it will be slow but maybe we can get some builder owners connected.
Hi All
My Name is Gavin vd Berg i am Scratch building a Tandem Airbike here in South Africa.
I am requesting some assistance - The plans i got are short a few vital pages and they have got some serious water damage on them.
I am looking for the page where the Control rods etc are shown with dimensions and all that.
I can send pics of what i am working with if proof is required. Been trying for a few months now to get either a digital copy or even a photo of the pages so i can get the dimensions and a better view as mine are as bout useful as loo paper to me.
Any form of assistance is welcome.
Hi Gavin,
I have all the plans for the Tandem Airbike if you still need.
Let me know.
Regards
Clint