Last time we flew the TTC we had no intake manifold  water injection.
Usually considered essential for turbo engines.
Wiring error on the water pump. I did not do it!

Intake manifold air temperature got up to 300 F.
With 60 inches of Hg manifold pressure and 8000 RPM  this would have
blown a piston engine sky high.

It still climbed out of sight in 27 seconds.
Then it climbed 75 to 80 degrees near vertical  some where
between 90 and 110 kts.
That translated to something  like 10,000 feet per minute.

I was worried about the engine.
So I set up the Maximite to record compression. I expected
to see some cracked apex seals.

Nothing. The engine came through OK.

Here are the plots of the compression data.
Each spike is one rotor face compression.

And the take off video.

If we had wider blades on the prop we could jack the boost up
to 80 inches of Hg. At 8000 RPM the tips are going super sonic.

I don't think we need it but it is an option if we don't quite get the record.

We will fly it again tomorrow after noon at Oxnard airport.

Paul Lamar

Paul, how does that program print the graph?

Steve Carlisle

The Maximite program does not do it.
It stores the data as a comma delimited text file. Here is the raw data.
It is basically just text so you can read it with any simple editor.

Then you load it into a spread sheet program and that can plot it.
I use free LibreOffficeCalc running on Linux.

Paul Lamar

   Does the ttc engine have side port exhaust?
   Richie Barrow

   No. All p-ports.

   Paul Lamar



How much intake to exhaust overlap are you running?

Richie Barrow

P-Ports give you a lot. Just like a jet engine. The connection
is never closed.

This is mainly due to the depression in the rotor face.

The rotary is a continuous combustion engine more like a turbine
engine rather than a piston engine. The fact alone that it fires
once per rev is a clue.

Piston engine concepts of valve over lap can not be used.
The dynamics of the gas flow make it work. Same as a jet engine.

Paul Lamar


   I was thinking more about  possible fresh fuel dilution and its effect  on elevated exhaust temps on the turbocharger?.

   Richie Barrow


   The reason the exhaust is hot is because there are no exhaust valves.
   Curtis Wright determined back in the late 40's that 20% of the exhaust energy was dissipated by
   the exhaust valves. That is the reason the FAA demands you test your certified aircraft
   engine each year for compression leakage. If you are leaking compression it is probably
   a leaking  exhaust valve. The heat in the exhaust valve is partially dissipated by the exhaust
   valve seat. If there is bad contact between valve and seat the heat dissipation is
   reduced and the valve runs hotter.

   If you don't fix it sooner... rather than later.... the exhaust valve head
   will fall off and destroy your piston engine.


   Paul Lamar

   That makes sence.
   Im wondering about the higher exhaust temps effect on the turbocharger.
   Early factory pp engines here ,had limited reliability with the turbos fitted.
   Has the silicon nitride  bearings and watercooled housings of the gtx  enough capacity to handle the higher temps?

Richie Barrow

For an aircraft you use the biggest turbo you can get. The larger mass of the turbine
is then less affected by the heat. In our case a GT40. Our turbo shows no signs of distress.
There is no cowl so that helps to cool everything.


The reason this is not done in cars is the turbo RPM and boost needs to accelerate
quickly. You also don't have a blast of air from a prop to cool things..

Not a factor in airplanes.

Paul Lamar

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