Deltahawk finally archieved certification!

Is there anywhere a detailed description of its construction? So far what I have seen is very superficial.
 
here you are:
View: https://www.youtube.com/watch?v=vJkA8VI6QdY&ab_channel=DeltaHawkJetFuelEngines


One of the problem with that engine is, that it was ment to du without a gear reduction, but they increased the rpm up to 3000 rpm, which is to high for a direct drive.

The concept of the engine is simple and elegant, but I guess they had a lot of trouble with cold starting and peak pressure. I believe they had to increase the compression ratio as much as possible to make it start (the exhaust port closes very late on two stroke engines) and faced difficulties to let it operate with typical Diesel pressures. Finally, they had to increase the engine speed to reduce the peak pressure and ended with 3000 rpm.
 
Honestly speaking, given that today general aviation is under pressure for noise, I don't understand why makers keep living fast turning toothpick props. Naca proved aeons ago that great noise reduction coupled with better performance is possible with a slow turning paddle prop. Tested on a Stinson Sentinel.
 
I do agree that 3000 rpm is to much, but we allready talked about that test with the Stinson Sentinel. I believe the torque of the propeller could have really been an issue. For higher powerd planes, a single prop with such a low speed would make the plane uncontrolable.
 
No it would not. The original test report had no mention of any such problems. Plus T=force x moment arm.
 
As I remember the report, this Stinson had very little power, something slightly above 100 Hp, please correct me if I'm wrong. To reduce the propeller load for a 360 HP plane (still not unusual for a SEP), the torque would be three times higher and the prop would be impractical huge. You can’t deny:

P=2π*n*M

which clearly shows, if the rotational speed “n” is going down, the torque “M” has to go up for the same power.
 
So what? It is pretty obvious that compared to say the Spitfire/109, the torque problem would be minimal. Absolutely inconsequential compared to the massive benefits. That excuse is very similar to what one American author posted as a serious defect of propfans in airliners: Someone may wander into the whirling blades, therefore propfans are dangerous.
 
It would require a giant prop, wow wood a SR-22 look like with a four meter prop?
 
Why should the prop be gigantic? The idea is not to increase diameter, it is to increase the number and width of blades.
 
The idea behind that particular Stinson was to reduce prop loading by using a larger, slow revving prop. It doesn’t work to reduce the prop speed without increasing the diameter, otherwise the angle of the blades would become too steep and the efficiency would be reduced.
 

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