Czech Mate

[Leo]

Just finished.
Insulated cups, coffee mugs, etc. available soon!

Blue Skies Sherm!

[SpinB]

Re: Czech Mate

She looks good, Sir! I'll miss her and Mr. Smoot ripping up the sky! Thanks for posting!

....still heartbroken

-spinny

[Jukka]

Re: Czech Mate

Awesome drawing/painting.

What is the efficiency of those clipped props ?

[Plane Nuts]

Re: Czech Mate

Awesome drawing/painting.

What is the efficiency of those clipped props ?

Simplicity. When Precious Metal had the clipped prop tips CNC profiled it picked up 56 MPH.

[Jukka]

Re: Czech Mate

Simplicity. When Precious Metal had the clipped prop tips CNC profiled it picked up 56 MPH.

So they are very efficient then.

[Plane Nuts]

Re: Czech Mate

So they are very efficient then.

Let me expand on my reply. When a propeller that is too large is fitted to an airplane the blades are shortened with a straight cut because it is simple and costs less not for efficiency. Attached is a photo of a CNC profiled blade on Precious Metal which gave a 56 MPH increase in speed.

[RAD2LTR]

Re: Czech Mate

In the case of Czech Mate, I believe the prop was actually too small for the power produced, but it HAD to be the size it was due to the lack of ground clearance. They still had to run the oleos pumped all the way up, as well as take off and land in a 3 point attitude, like Rare Bear, for the same reason.

The square tips may or may not have been efficient, it might have been interesting to see if reprofiled tips would have given them more speed they way they did with Precious Metal. Sadly we will never know. I think CM could have had more speed in it with some further refinements, but who knows. Hopefully the interest to build a similar racer will be kindled and we can find out in the future.

Will

[marada mx3]

Re: Czech Mate

In the case of Czech Mate, I believe the prop was actually too small for the power produced, but it HAD to be the size it was due to the lack of ground clearance. They still had to run the oleos pumped all the way up, as well as take off and land in a 3 point attitude, like Rare Bear, for the same reason.

The square tips may or may not have been efficient, it might have been interesting to see if reprofiled tips would have given them more speed they way they did with Precious Metal. Sadly we will never know. I think CM could have had more speed in it with some further refinements, but who knows. Hopefully the interest to build a similar racer will be kindled and we can find out in the future.

Will

Not to be insensitive or morbid, but is there anything left of CM's airframe to rebuild? I've seen the same question already come up about Texas Raiders, and there are hundreds of photos that answer that question. In CM's case, there are probably only a select few people that have seen the remains, so it makes one wonder. Could this be a similar situation to Tsunami?
Thanks.

[RAD2LTR]

Re: Czech Mate

Not to be insensitive or morbid, but is there anything left of CM's airframe to rebuild? I've seen the same question already come up about Texas Raiders, and there are hundreds of photos that answer that question. In CM's case, there are probably only a select few people that have seen the remains, so it makes one wonder. Could this be a similar situation to Tsunami?
Thanks.

I have no clue what was left. I'm sure it could be rebuilt as Yaks are a tube frame fuselage, but I think it would make sense to start over with a new airframe altogether. There are plenty of Yak 11s out there. Add a wing with a better airfoil and perhaps move the cockpit forward (from where CMs was) a little, and off you go.

Will

[GRNDP51]

Re: Czech Mate

Not to be insensitive or morbid, but is there anything left of CM's airframe to rebuild? I've seen the same question already come up about Texas Raiders, and there are hundreds of photos that answer that question. In CM's case, there are probably only a select few people that have seen the remains, so it makes one wonder. Could this be a similar situation to Tsunami?
Thanks.

From the story it was hard to determine how the impact was, but the prelim NTSB report had a photo of CM?s attitude towards the ground, and I would say there isn?t much left.

[BellCobraIV]

Re: Czech Mate

Let me expand on my reply. When a propeller that is too large is fitted to an airplane the blades are shortened with a straight cut because it is simple and costs less not for efficiency. Attached is a photo of a CNC profiled blade on Precious Metal which gave a 56 MPH increase in speed.

Czech Mate had squared off Aero Products hollow steel blades. Therefore profiling the ends would have been not possible.

[Plane Nuts]

Re: Czech Mate

Czech Mate had squared off Aero Products hollow steel blades. Therefore profiling the ends would have been not possible.

Thank you for your answer. So that brings more questions to mind, once the hollow blades were shortened how were the ends closed off and how much was removed from the blades?

[TWD]

Re: Czech Mate

[

I just measured one of the tips that was removed. It is 14.25" tall. The cord at the cut is 12.5" The holes to fill are a tick more than 3/8 "
Larry Klassen told me that he braised the ends to fill them.


QUOTE=Plane Nuts;147337]Thank you for your answer. So that brings more questions to mind, once the hollow blades were shortened how were the ends closed off and how much was removed from the blades?[/QUOTE]

[deepsky]

Re: Czech Mate

That's fantastic, Leo! Well done!

[Plane Nuts]

Re: Czech Mate

[

I just measured one of the tips that was removed. It is 14.25" tall. The cord at the cut is 12.5" The holes to fill are a tick more than 3/8 "
Larry Klassen told me that he braised the ends to fill them.


QUOTE=Plane Nuts;147337]Thank you for your answer. So that brings more questions to mind, once the hollow blades were shortened how were the ends closed off and how much was removed from the blades?

[/QUOTE]

Thank you for your answer. As a mechanic and gearhead I like to know how mods are done.