Diamond Turboprop: Balancing Innovation and Risk

I'm pretty impressed overall with Diamond Aircraft. They've very quietly been making innovative, high-quality aircraft for years. They have a firm foothold in the training market with their economical DA20, and the DA40 is well-regarded in the 4-place piston market by those who fly it. Their DA42 Twin Star is probably the first meaningful piston twin developed in decades. With its diesel motors, FADEC and advanced aerodynamic design it's a really cool airplane.

A few years ago, there was a lot of talk about Very Light Jets. The market is absolutely there. The rich and famous are buying Cirrus SR22s like hotcakes. Cessna has their C350 and C400 and Diamond's DA40 and/or DA50 could be included at the lower end of that class. I'm sure that all those SR22 and C400 owners love their aircraft, but like any pilot, they'll eventually want something bigger and faster. The Very Light Jet class (including, or not, Diamond's own D-Jet) could be the perfect step. However, that market isn't panning out like everyone hoped. Cirrus co-founder Alan Klapmeier started pursuing the alternative path of building a 6-place turboprop single, the Kestrel. Turboprop singles appear much easier to deal with as far as development goes. They appear more familiar to piston single pilots and in many cases their performance rivals or exceeds that of the proposed VLJs. (If you don't believe me, just take a look at the specs for the Kestrel or the TBM-900.)

It appears that Diamond has realized the potential of this market as well. They've recently announced the first flight of the DA50-JP7, a 7-place turboprop version of their DA50. The intake under the engine doesn't make it the prettiest airplane I've ever seen, but the Ukrainian Motor Sich JSC AI-450S turbine engine has the potential to be an impressive powerplant. FlyingMag.com reports reports that the motor provides 465 hp for takeoff and Diamond claims that the motor has a 20% lower fuel burn than equivalent turbine engines. (At today's fuel prices that mean $45-$100 per hour savings over an equivalent competitor.)

If that fuel burn figure is correct and the airplane is roomy enough, the DA50-JP7 could be a great step up for owners tooking to go higher and faster. Unfortunately, I'm a little concerned. Diamond advertises that their new aircraft is a 7-place. While that's a nice idea, the airframe is just an expanded DA50 and only appears to have two doors. I've been in a C-210 and while seats 5 & 6 were present, they were not suitable for large people or long flights. Most, if not all of the other 6-place turboprop singles have gone for a larger cabin and club-style seating. Even most of the light twins work to make their aircraft feel more cabin class than GA. Unless Diamond has done something magical with the seating configuration and access to the back seats, I'm worried that their new airplane will effectively only be a 4-place.

I'm also a little worried about their choice of motor. It looks great on paper, but so did the Thielert diesel. The Thielert had FADEC, was turbocharged, had great fuel consumption...and it was a disaster. The Time Between Replacement (TBR, not TBO) was too low, the company support wasn't great and Thielert ended up going bankrupt. Diamond must have gone crazy trying to support their Thielert-equipped aircraft and even acquired the rights to build the engine themselves under a new brand called Austro. Things are looking up thanks to Austro, and TCM has since started building diesels as well, but it's been a long road.

Now, Diamond has another new engine design that promises to be innovative and more efficient than anything else on the market. I want that to happen...GA needs companies to innovate like this. Motor Sich appears to be a major engine manufacturer, but how much time and energy do they have to support a turboprop for a GA aircraft? Worse yet, Ukraine is in a de facto war with Vladimir Putin's Russia. How will the instability of that conflict impact support for the engine now, or future availability? Diamond's press release emphasizes the fact that their Austro Engine division is working closely Motor Sich. I hope that's the case! Maybe they're setting things up to license the engine on their own under the Austro brand...or something. After the disaster that was Thielert, Diamond needs to be able to assure DA50-JP7 owners that engines, parts and support will be available for the life of the aircraft.

I hope Diamond can pull this all off. Having spent a couple thousand hours behind single turboprops, I'm a fan of the concept. They're more powerful and reliable than a piston, and there's something to be said for having reverse thrust available for landing and taxi. If Diamond's claims on fuel efficiency are true the AI-450S may be worth the extra cost for many owners. It'd be a major move that could send ripples throughout all of General Aviation. There are thousands of high-performance piston single owners that are looking to move up. Maybe the DA50-JP7 will be what they were waiting for.