Speedring Cowl for a Rotec - Possible Group Order?

[johnkerr]

I would be interested in participating if I haven't sold before the order is set.

Would it be worthwhile to get a price from Hans for the mounting hardware?

John

[dougm]

I'll be using original Waco drawings and scaling them down to fit the Rotec. I can't guarantee that Hans fittings will work as the diameter of the ring may not be the same. Even if they are close, they may not be "close enough". As they say "close enough" only works in horseshoes and hand grenades

[stearmoth]

Hi friends,
Concerning our speedring offer we think it will be worthwhile to give a clarification.
When we made our offer a few years ago, the company where we have been allowed to use their equipment (very large dia metal forming lathe) by using our own made wooden forms (yes, we needed 3 differnet forms to achieve the goal), was still active. Shortly after the owner sold all machinery and the factory was wipped off to make place for a appartement building. We tried to purchase the lathe, but failed to do so.
We still would have the possiblity to let the raw formings done by another manaufacturer and do the finishing ourselfs. However, we later found, that a real market doesn't exist outside USA. We got only few requests for a speedring and we also would need a few, when we would let the manufacturer make some pieces for us. One or two rings only would be too expensive. The offer we made then would be for a softly sanded aluminum finish (not polished) but including the mounting hardware attached the the speedring.
Of course the rel. high shipping cost (and risk of damage if not packed in a wooden box) made our price a looser. Hence we no more made any marketing activity. It would be differnet if there would be a market in our coutry or central Europe - which definitely doesn't exist.
Sometimes I feel, we both would match more you Americans that our Swiss fellows! As I use to say: If someone wants a safe, beautifully restored and attractive looking antique biplane in this country, which he can afford, then he has to build one! This is what we intended and succeeded to do with our "poor man's Waco" Vintage Hatz .We now have about 70 hours flight time and 120 landings and still going strong...

However, in that price the especially CNC grinded rocker covers, which hold the base bars for the mounting attachments , was not included. If somebody wants an engine mounted (swinging with the engine) speedring, we strongly recommand the use of special rockercovers, which can take the possible forces applied by a speedring. If somebody wants a bumpcowl, which is attached statically to the fuselage, then there is no problem.
In a first instance we wanted to set the attachment hardware atop the oil inlet and outlet lines placed on the underpart of the rocker cover. We then felt, that the risk of an oilline failure was too high, hence we neglected this idea!!!

Please feel free to ask any questions you might have and we are here to give advice whereever it is wanted. We know, our homepage still needs to be actualised and when done, more details will be published.
We also want to make comparison flights in a row with identical weather conditions with and without the speedring in order to find out which set-up is better for cooling and higher speed.

Stay tuned - we hope both to come back to Brodhead and Osh next year (the old guy will then be retired and if he finds a buck left, will come to your beautiful antiique biplane scene for sure!)

Kindest regards

Hans & Sam, H.C.#78, Switzerland

[dougm]

Regarding mounting the speed ring, Hans it looks like you experimented with several options before going to special rocker covers. Also, I believe you have four mounting points correct? I know WACO put a mounting point on each cylinder so the loads were spread across seven points. I have photos and measurements of the updated system that is currently being used with brackets attaching to the rocker covers. I'll have to modify them some to fit the Rotec and have some sketches of the parts I plan on having water jet cut. Also, I plan on having mounting point per cylinder for a total of nine. This should spread out the loads and keep the clamping pressure evenly distributed.

Obviously, the Rotec has only 2 screws holding down the rocker covers as opposed to 4 or 6 on the larger radials, but I have an idea I think will work to compensate for that.

[stearmoth]

Hi Doug and all,

In reply to your thoughts I will explain some more:
You are right, the Rotec rocker covers only have have 2 screws wheras others have 4, which is much better of course. At the beginning we had problems keeping our covers oil tight (it was difficult to get them tight again after adjusting the valve play). The problem was that the covers theorethically flat plane was a little convex and with the 2 screws close to the mniddle of the cover you couldn't get them tight.
We then decided to let fabricate by CNC 4 special covers from high quality aluminum (not cast type), which also cover the speedring attachment bar. We choose only 4 instead of 9 only due to economic reasons and we still feel that our decision was right. The speedring is a tight fit and you cannot see, that it is slightly out of a circle (this would be better with a 9 point fit, of course).
Sam later decided to let have made 5 more covers (without holding bars, because 4 seem to be sufficient), but they have a O-ring for sealant (which is his design and luckily Rotec switched to the O-ring solution as well later on). Now, our engine is absolutely clean, no more oiling ... haha!.
If the Rotec rocker covers would be differntly designed, it would be easyier to attach brackets for the speedring by the two screws.
In any case I would still not recommand the attachment of the speedringto the oill lines of the rocker cover base!

Kind regards
Hans & Sam, H.C.#78, Switzerland

[johnkerr]

I may still be interested

John Kerr

[dougm]

Thanks John. The initial work on the CAD drawings for the speed ring was supposed to be done while I was at OSH. I'll be checking later this week on it.

[dougm]

Still working on this. The guy doing the CAD drawings is doing this as a side job and was working on some other drawings for me for my Rotec order. This should get moving next week. Stay tuned...

[alvinsager]

Hi Guys,
I have no interest in a speedring, since I am using a flat motor, but I remember reading about the construction of Samson or possibly Delmar Benjamin's Gee Bee that the builder, Steve Wolf, made his cowling from the housing of an axial exhaust fan that had the proper dimensions. Lots of cutting later you may have something!
Good luck,
Al

[johnkerr]

Ed, do you have any further information on the speed ring you are exploring?
What mounting considerations are you working on?

John