29 Mar 2024, 10:10 [ UTC - 5; DST ]
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Post subject: Re: Raptor open house Oct. 21st Posted: 29 Sep 2017, 15:25 |
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Joined: 10/31/16 Posts: 283 Post Likes: +217
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Username Protected wrote: Cherokee County Georgia KCNI, 38 miles from my airport. http://www.raptor-aircraft.com/home.htmlSaw that myself, and they're making steady progress. Whether or not it works out is another question, but I give them props for working through the problems so far. Personally I think it should've been kept as a small turboprop just for engine reliability, but it's their plane design. They can probably get that auto engine for a boatload less than even a used 500SHP-750SHP turboprop. They're probably also counting on the auto engine sipping gas to get the range. If nothing else, it's been interesting to watch. I may have to pop down there using airmiles just to see.
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Post subject: Re: Raptor open house Oct. 21st Posted: 29 Sep 2017, 16:37 |
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Joined: 03/27/10 Posts: 331 Post Likes: +196 Location: GTU - Georgetown, Tx
Aircraft: 65 Deb C33, RV-6
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I'm pretty sure I am headed to the open house. I am also close to putting down the $2,000 deposit. At the same time, I think I see the way this all falls apart: 1. They produce a flyable prototype and announce the performance data. 2. Deposits transfer from escrow to Raptor, Inc. (about 2.5 million) 3. Raptor, Inc goes bankrupt. 4. Raptor, Inc is made whole, you the depositor -- not so much. But a grown man has a right to fantasize over 230 ktas cruise at 25,000', pressurized with a chute and deice, full digital panel all for about $150k.
_________________ B-25 co-pilot RV6 Formation Debonair CFI/CFII/MEI Washed up Fighter Pilot (F-4s, F-16s)
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Post subject: Re: Raptor open house Oct. 21st Posted: 29 Sep 2017, 22:05 |
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Joined: 03/15/16 Posts: 695 Post Likes: +365 Location: Charlotte NC
Aircraft: Piper Mirage
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Too good to be true. But I'm off that day so I may swing by!
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Post subject: Re: Raptor open house Oct. 21st Posted: 30 Sep 2017, 07:38 |
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Joined: 11/20/14 Posts: 6452 Post Likes: +4524
Aircraft: V35
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I'd believe 200 knots on 18 to 20 GPH.In other words, a more aerodynamic TN A36. A little more room, a little more speed. 230 knots on 7gph, that's asking a lot from both a drag reduction and an engine BSFC perspective.
It kind of reminds me of the Cirrus kit VK30 that had impressive performance compared to certified airplanes. However, the handling was not certifiable. Too easy to stall/spin. They could easily match the VK30's numbers, but can anyone do so without the handling issues?
Cirrus was smart enough to use an aircraft engine in theirs. As far as I'm concerned the Pond Racer showed the problems with unrealistic expectations on high performance auto conversions.
I would love to see a new airplane offering VK30 levels of performance with new tech that tames the handling issues... almost certainly with Autopilot based envelope protection. That would work, might even be something you could certify. It's basically the approach the military took with many fighters.... design the wing and aerodynamics for max performance, make it safe to fly with automation.
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Post subject: Re: Raptor open house Oct. 21st Posted: 02 Oct 2017, 07:40 |
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Joined: 03/22/16 Posts: 692 Post Likes: +356
Aircraft: SR20
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Interesting.... Kcni is my home airport. I may try to swing by. I never knew they were even there.
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Post subject: Re: Raptor open house Oct. 21st Posted: 24 Oct 2017, 08:55 |
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Joined: 10/23/17 Posts: 5 Post Likes: +6
Aircraft: M20F-"SE"
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I'm really glad they decided to do the open house and making the effort to go was well worth it. There ware probably around 300 people there. Currently, I am a Mooney owner and was asked by one of the members here to share my experience at the open house.
They had the prototype up on it's wheels and we got to sit in the cockpit and play a little.
It's very wide in the cabin. Very much like sitting in my 2015 Sierra HD. You can see the Garmin g3X touch screens are far apart. the GTN 750 is in the lower, center panel. The oval thing is the climate control.
The side stick will take come getting used to, but I like it. There is enough space under the seats to place a carry-on size rollerboard leaving plenty of room for feet in the back.
I talked quite a bit with Jeff. He is the guy that used to work at Velocity. One of the concerns I had was the canard in icing conditions. I told him about my friend's Varieze and how it doesn't even like to fly in the rain. The canard Rutan used was not the best. It was good for speed, but nothing else. The airfoil on the Raptor is a proven to work well in icing, rain, bugs. In addition, Jeff was asked about flaps. Basically, flaps load the canard creating a higher AOA and higher stall speed. Since the canard will now stall at a faster overall airspeed, flaps defeat the purpose by which they were intended.
The engine:
This is where there is alot of debate. My personal feeling is, this is a good engine choice.
When I first heard of the engine choice, I asked about it and specifically noted that car engines don't have a good track record in airplanes. What I found out was, that os true of gas motors, but all the aviation diesels out there are automobile derivatives.
I know diesel so it doesn't scare me. I tune performance diesel trucks. I would have NO issue flying with this engine. Here's why.
The Audi engine is not only a proven, reliable engine in automobile use, but also in marine use. You can make an argument for the fact it doesn't work very hard in a car, but it does work hard in a boat. In fact, it runs 75% and higher in a boat. In an airplane, we RARELY run our engine more than 75% power, even if you are turbo charged. To say the 3.0 won't hold up to running 100% all the time is probably a true statement, but it never does. If a Lyc or Conti engine was run at 100% power all the time, they wouldn't last long either. A better test is, will it run at 75% power for four hour stretches with an hour rest time. That would be more typical of a flight. When I tow with my diesel truck, I am towing at 75%+ power for hours on end. Diesels like to work. Gas engines don't. With a diesel, there is a ton of low-end torque that is not available in a gas engine. Also, the torque curve is relatively flat. This means you could throttle the engine back at cruise, turn a big prop and really move out while barely taxing the engine. In addition, if you are light, it is very feasible to do what the airliners do; derate your take-off power. The main difference between gas and diesel are the internals. They are much beefier then their gas cousins. In addition, this is a fairly low-compression diesel at 16.9:1. this means there is alot of "headroom" for making safe power.
The Raptor is probably 70% done. Their target date for the first flight is March.
The prototype will probably be heavier than they originally planned, but as the production begins, Mark (the structural engineer) is going through all the parts to see what can be made lighter. Right now, they are just looking to get it in the air.
Overall, it is very cool to see the operation in person. You can really see the planning and the CAD at work. Glad I took the time to go down and see it in person!
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Post subject: Re: Raptor open house Oct. 21st Posted: 24 Oct 2017, 14:08 |
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Joined: 10/23/17 Posts: 5 Post Likes: +6
Aircraft: M20F-"SE"
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Username Protected wrote: What are the issues with the canard in icing/rain? A canard is a highly loaded airfoil. In the case of Rutan, it is laminar flow which is sensitive to contamination. I have a friend that flies a VArieze and anytime he flies in rain, he has to hold back on the stick. Any laminar flow airfoil is like this (the Mooney loses about 3 knots in the rain), but, being with a high loading, the critical AOA approaches pretty rapidly. This is why there are no flaps. Flaps load the canard even more, making a higher AOA required. Of course, that brings you closer to critical AOA for the canard and defeats the purpose for which flaps are intended. In this design, the canard airfoil is proven to operate in light contamination with no issues. IIRC, it is the same airfoil that is on the Velocity.
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Post subject: Re: Raptor open house Oct. 21st Posted: 24 Oct 2017, 20:19 |
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Joined: 08/10/14 Posts: 1730 Post Likes: +828 Location: Northwest Arkansas (KVBT)
Aircraft: TBM850
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Username Protected wrote: looks like a 200-300k investment, i'm curious to see the builders/buyers who embrace this and what their plans for insurance are to protect their investment Current target price is $130k per the website, but I'm in the minority who expect that $200k+ is more likely. With over 1,000 deposits it is likely to be a larger insurance market than other hard-to-insure experimentals, but this is a valid question especially for the first 25-50 aircraft in the air from the production molds. I know relatively little about EAB aircraft but followed the news about Evolution's issues which some have attributed to (the lack of) insurance. There is some hope that the difference between an airframe with a tractor-config turboprop with nose gear issues and a pusher piston will influence that equation.
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Post subject: Re: Raptor open house Oct. 21st Posted: 25 Oct 2017, 00:05 |
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Joined: 05/13/11 Posts: 127 Post Likes: +49
Aircraft: None
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I don't know specifics regarding canards, but anecdotes: - Starship pivoted the canard fore and aft with flap deployment to shift it's center of lift - P180 has flaps on the forward wing that have a complicated inter-working with the main wing flaps (the P180 technically doesn't have a canard, but...) - Laminar flow wings don't like contamination. In rain, an SR22 loses ~8 kts, the last SR20 I flew lost closer to 10-12, and a DA40 loses about 10.
So... no flaps makes sense, and I don't get how they've protected it from contamination other than making it dirty to start with. But, as I said, I don't understand how these things work I've just heard and experienced anecdotes.
Re: Diesel car engine. The Theilert / Centurion / Austro is a mercedes-derived engine. The SMA is not. I'm actually not sure which others are automotive derived...? The Graflight was clean sheet I thought, as is the Deltahawk...
I agree that marine and aviation powerplants have similar duty cycles in concept, and have often thought about turning a 4 stroke outboard into a plane engine. However, if you look at the computer printouts of a marine engine, they generally spend less than 50% of their time running over 50% power. You can pull the codes on any modern outboard and see this. In fact, a duty cycle for a marine engine in "pleasure" use is 1 out of 8 hours at full power. It doesn't define the other 7, but in practice it's often at hull speed (like, under 20%). So I'm really not sure how that VW engine will do at 75% power for extended time - like most things, it'll depend on the quality of the cooling and lubrication.
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