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Diamond Aircraft developing R44 competitor

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Diamond Aircraft developing R44 competitor

Old 7th Apr 2017, 12:36
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Diamond Aircraft developing R44 competitor

A more credible new market entrant than some of the other attempts we've witnessed in recent years, given Diamond's solid track record in new product introduction. The reference to a "four stroke, jet fuel engine" suggests a diesel powerplant, possibly an SMA.



From Flight:
Pitched against the Robinson R44, the composite four-seat DART (Diamond Aircraft Rotary Trainer) 280 is projected to have an MTOW of 2,500 lb, a payload of 1,235 lb, energy absorbing retractable landing gear, a shrouded, electric tail rotor, and a 280 shp four-stroke jet-fuel engine.

First flight is scheduled in about 18 months, leading to certification about 12 months later.

The program will provide a stepping-stone to a family of rotorcraft, including a hybrid-electric quad tiltrotor.
I/C
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Old 7th Apr 2017, 13:57
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Excited to see this.
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Old 7th Apr 2017, 16:15
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Very interesting. Good luck with this one.
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Old 7th Apr 2017, 16:59
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A 4-stroke jet fuel engine....?

April joke?
 
Old 7th Apr 2017, 17:18
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Originally Posted by hueyracer View Post
A 4-stroke jet fuel engine....?

April joke?

Sounds like a diesel (Jet-A) piston engine to me...
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Old 7th Apr 2017, 17:19
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I assume a diesel engine which can burn Jet-A vs Avgas.

The electric tail rotor is what caught my interest...I would hope there will be a robust battery back up.
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Old 7th Apr 2017, 17:19
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Originally Posted by hueyracer View Post
A 4-stroke jet fuel engine....?

April joke?
a Thielert / Continental engine or an Austro Engine one.
Diamond used to mount both types on their DA40/DA42/DA62 fixed wings.

They run with normal car diesel or with jet A1, whatever you have access too.
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Old 7th Apr 2017, 18:05
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At last 30-40 KVA genset add on piston engine, plus 30 KVA electric motor, than DC/AC converter and extra battery = much weight penalty
Or they use some new technology which can go under CS27 certification.
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Old 7th Apr 2017, 19:32
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Originally Posted by 9Aplus View Post
At last 30-40 KVA genset add on piston engine, plus 30 KVA electric motor, than DC/AC converter and extra battery = much weight penalty
Or they use some new technology which can go under CS27 certification.
JOKE "Solar panels! They will cover the AC with solar panels! Night flight or IMC may be a problem." JOKE
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Old 8th Apr 2017, 01:05
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The electric tail rotor is interesting - but the above suggestion of 30-40Kva power generation requirement, and a 30Kva electric motor requirement, is not realistic.

I'd suggest perhaps 3-4Kva power generation requirement, and 2-3Kw electric motor would be quite adequate for a rotary aircraft of this size and weight.

Both of which are quite feasible, and coupled with a capable lightweight battery, would provide all the power and backup needed.
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Old 8th Apr 2017, 01:22
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Originally Posted by hueyracer View Post
A 4-stroke jet fuel engine....?

April joke?
The name is : turbine Remember, A turbine is a linear 4 stroke engine :
Admission/compression/linear explosion(continuous)/gas release...
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Old 8th Apr 2017, 07:48
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@onetrack
Can we agree that 4 seat helicopter of that size need approx 150 kW (201 hp) engine.
Your opinion is that just 2% of that power is enough in tail?!

More likely, you may need up to 20-30% of that power in tail... during hover or hover taxi.
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Old 8th Apr 2017, 08:17
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I thought that the benefits of retractable landing gear were in streamlining, something that is only warranted for high speed craft?

Or could the attraction be that retractable gear is lighter than skids?

Given Diamond Aitcraft has significant experience with integrating gimbals, I'm interested to see the ground clearance.

Height adjustable gear would be innovative!

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Old 8th Apr 2017, 11:49
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Originally Posted by BOBAKAT View Post
The name is : turbine Remember, A turbine is a linear 4 stroke engine :
Admission/compression/linear explosion(continuous)/gas release...
As pointed out already, Diamond have extensive experience with piston diesels that run on Jet A1.
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Old 8th Apr 2017, 13:54
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I would love to see this project come to market, but its unlikely to do so with any of the existing or soon-to-be launched 4-stroke diesel engines...they are simple too heavy. If they do use any of the existing diesels then it will be a very expensive helicopter (in R44 terms).

I have spent a lot of time over the last few years looking in detail at all of the realistic engine options for a helicopter of this weight and the existing diesels simply don't work in helicopters. While on the face of it some of them appear to look comparable with Lycomings, by the time you de-rate them enough to be reliable they are very heavy. The 4-cylinder SMA engine is unlikely to ever be released above its current power rating as its reliability drops off very quickly above the current design point. The 6-cylinder unit will offer more power, but will be heavy and expensive.

Similarly they are claiming, 1235/2500lb =49.4% useful load out of a piston powered helicopter! Many of the turbine machines don't achieve this! Robinson and Guimbal are at around 40% with relatively light Lycoming engines. A suitably de-rated diesel engine will be significantly heavier, as will retractable landing gear.

It is theoretically possible to have a diesel engine that is light enough to work in a helicopter, but it wouldn't be the same configuration as would be used in an aeroplane and hence they would need to develop it themselves.

If they move forwards with this it will likely end up with the Lycoming IO-540-AE1A5 (R44 Raven 2's engine) or similar and a 1000lb payload.

Similarly, with all the resources in the world, they will not be ready in 18 months with the technical development they are proposing...maybe in 60 months.

Good luck chaps, look forward to seeing it flying.

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Old 8th Apr 2017, 22:09
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Darn it , I had an interview in London the other week but I took another position . Will they be building in Canada or Europe ?.
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Old 9th Apr 2017, 05:23
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A few years back Robinson took a long look at installing a recip diesel in their R44, but concluded it was not worth the trouble.

Personally, I think we will soon see a new generation of small turboshaft engines coming to market that will be a much better option.
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Old 9th Apr 2017, 05:38
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It's almost unbelievable, that in 2017 we are talking about installing 1940's technology (Lycoming aircooled opposed reciprocating donk) in a new design.

What other industry, full of technology would use a two valve pushrod engine?

Surely with modern design/manufacturing/ECU technology we could have turbine engines in any new designs.
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Old 9th Apr 2017, 11:45
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9Aplus - O.K., maybe I was being a little over-optimistic as regards the design improvement potential of the Diamond engineers electric-powered fenestron tail rotor.

However, Prof. J. Gordon Leishman at the University of Maryland tells us in his helicopter aerodynamics writings, that the typical open tail rotor of your average helicopter consumes around "5% to 10% of the engine power".

It's not unreasonable to presume that an electrically-driven shrouded tail rotor of a perfected new design, would be able to halve that power requirement. Therefore 2.5% to 5% of engine power required for the tail rotor could be possible.
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Old 9th Apr 2017, 12:28
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riff raff
Tend to agree regarding new turbo shaft engines
With the excessive costs of present suppliers\ manufacturers mature designs (old paid for) it should encourages new companies.

PBS - Aircraft Engines
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