De-Icing


In yet another innovation first, the Raptor will be equipped with the first 'Always On', and 'Better than Free to Operate' de-icing system for the diesel and Adept versions.

How, you ask? Well, we have a diesel engine that is generating a lot of heat. It's normally water cooled and we decided that all that heat was going to be wasted and worse off we would have to cool it with outside air which creates cooling drag. 

So, we have come up with a simple, yet ingenious, solution (thanks Tan for your brilliance, as usual). We are going to create a closed loop system of small diameter stainless steel tubing that is embedded into the leading edges of the main wing and fore plane, the leading edge of the air intake as well as the aircraft nose. This loop will pull heat from the engine radiator using a heat exchanger. It will be always on, running very low pressure with a small pump to drive it. It will be filled with a solution containing anti-freeze. 

There will be dual loops with outbounds on the leading edge and top of the wing and returns on the leading edge and bottom of the wing. This should prevent any runback situation. We will have more details and diagrams later on showing the configuration. 

The system will also be thermostatically controlled in order to prevent overheating in warmer conditions.

There will also be another air heat exchanger in the nose just in front of the windshield that we can blow air through that will exit in small vents in front of the windshield in order to provide de-icing for it. This air heat exchanger will be connected to a similar loop coming from the same heat exchanger pulling heat from the engine radiator.

In the wing tanks that are inside the wing strakes we will not only have the stainless tubing built into the leading edges of the strake but we'll also have it inside the tanks with the purpose of keeping the fuel warm. This way you can run regular diesel or jet fuel without adding any Prist in order to prevent the fuel from thickening in the cold temperatures found at altitude.

With this system we get the following benefits:

1. Initial cost is very low as the parts required are readily available
2. Installation is straight-forward
3. Does not disrupt the air flow on the critical leading edges of the wings unlike pneumatic boots
4. Does not use any horsepower to operate unlike electric de-ice strips that require a large alternator
5. Does not require constant top-ups or create a mess like glycol systems 
6. Is always on thereby preventing ice from ever forming
7. Actually improves the efficiency of the aircraft by reducing the cooling drag by dissipating engine heat out through surfaces that are already being cooled by the oncoming air
8. Does not cost anything to operate and given that we'll probably pick up a couple of knots from reduced cooling drag it will actually 'pay' you.

So, all in all we'd call this a Win, Win, Win. Even if you never fly in icing conditions you will still benefit from this system by way of better efficiency through reduced cooling drag.

This is yet another example of why it's still a good thing that we're still finalizing all the aspects of the design as these ideas and innovations just keep coming.

For the propellor we will likely require a de-icing boot although the heat from the exhaust and the remaining hot air from the cooling system will be directed over the prop in order to minimize the need for a boot.

The Raptor is truly going to be the state of the art in general aviation!





For the turboprop version:

The engine exhaust blows directly on the prop in much the same way as it does on the Piaggio Avanti so de-ice boots are not required on the prop for a turboprop. We are considering the idea of extracting some of the exhaust heat using a shroud to use the same closed loop system as the diesel for de-icing on the surfaces. 

If this is not feasible we will be using an electrically heated lip on the engine intake and also use engine bleed air on the external windshield. The option exists to use electrically heated leading edges or better yet de-ice boots on the wing and canard, the additional cost would be about $15,000. We will consider this depending on demand. We will also be considering different options for heating the nose of the aircraft. 

The Raptor will not initially be certified for known icing. 
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