Raptor Composite Aircraft

Help Support HomeBuiltAirplanes.com:

rv6ejguy

Well-Known Member
I'm new here but there's a lot of NEGATIVE outlooks on a guy that's willing to put it all on the line for everyone to see.

In the turbine world, the fuel is used as an oil cooler. Also, they preheat the fuel in the turbine applications too so I don't see what the worry is about the heat of the fuel.

In all honesty, the structure is more of a problem to heat than the fuel so it might be more productive to calculate the heat retention of the structure rather than speculate the radiant heat to the fuel tanks.
I don't think you understand what Peter intended to do by passing fuel through through one intercooler stage. He was trying reduce intake charge temperatures. This varies considerably compared with heating the fuel through a turbine engine oil cooler as is commonly done on production aircraft.

With the 7 to 1 PR required at FL250 and the turbos he's selected, the CDTs will exceed 400F easily. This coupled with the intake mass flow, represents a huge amount of energy to be dissipated. The fuel could reach critically high temperatures in the space of less than a couple of hours.

Don't consider comments here negative but rather a reality check on Peter's projections. We already know that his range and payload numbers can't be met because the aircraft is 1000-1200 pounds overweight. Something is gonna have to give in the TO, ROC and ceiling projections if he gets the payload back by raising the gross 1200 pounds more.

We also know that the TAS vs. fuel flow numbers are highly improbable for an aircraft with this wetted area.

These are inescapable facts.

I've watched every YT vid on Raptor and just finished talking to Jeff Kerlo 2 days ago at Reno who gave me a lot more insight into this project.

Do you have some technical details to add or discuss on this project which would put the previous discussions here on HBA in question?

Rik-

Well-Known Member
I don't think you understand what Peter intended to do by passing fuel through through one intercooler stage. He was trying reduce intake charge temperatures. This varies considerably compared with heating the fuel through a turbine engine oil cooler as is commonly done on production aircraft.

With the 7 to 1 PR required at FL250 and the turbos he's selected, the CDTs will exceed 400F easily. This coupled with the intake mass flow, represents a huge amount of energy to be dissipated. The fuel could reach critically high temperatures in the space of less than a couple of hours.

Don't consider comments here negative but rather a reality check on Peter's projections. We already know that his range and payload numbers can't be met because the aircraft is 1000-1200 pounds overweight. Something is gonna have to give in the TO, ROC and ceiling projections if he gets the payload back by raising the gross 1200 pounds more.

We also know that the TAS vs. fuel flow numbers are highly improbable for an aircraft with this wetted area.

These are inescapable facts.

I've watched every YT vid on Raptor and just finished talking to Jeff Kerlo 2 days ago at Reno who gave me a lot more insight into this project.

Do you have some technical details to add or discuss on this project which would put the previous discussions here on HBA in question?
I'm not here to defend the guy; you've found the wrong guy for that, nor am I here to rewrite this thread. I simply made an observation and it's not really disputable now is it.

So, is he running the fuel through the intercooler then back to the tank/tanks or directly into the fuel system of the Audi engine?

I'm asking as I don't have the slightest idea.

bmcj

Well-Known Member
HBA Supporter
By the way, welcome to HBA Rik. I hope you stick around and participate. We always welcome new member input.

Topaz

Super Moderator
Staff member
Log Member
Moderator Note: Just deleted two posts that continued the off-topic sniping between members. PM's sent.

Tragically, this thread will be experiencing "technical difficulties" for precisely the next 48 hours. I have it on very good authority that it will reopen at that time. I'm quite sure everyone will be happy to just talk about Raptor once we somehow manage to overcome these unfortunate "technical difficulties" and the thread reopens.
_____________________

Moderator Note: The thread is now back open.

Last edited:

flyboy2160

Well-Known Member
All right! I was having Raptor Thread Withdrawal Syndrome and was about to schedule therapy. T's Timeout, You're Grounded, Bad Kids Sit In The Corner remedy was the perfect punishment for some dubious behavior.

The shimmy continues. He's getting exactly contradictory advice on Youtube about how to fix it, including an admonition from a claimed aerospace engineer who says he shouldn't be using a gear intended for an engine mounted right over it with an engine mounted at the rear!

Turns out he used a positive rake that was different from what Lancair uses with the strut he has and he increased the tire size. Pazmany who?

Last edited:

BJC

Well-Known Member
HBA Supporter
He's getting exactly contradictory advice on Youtube about how to fix it. Turns out he used a positive rake that was different from what Lancair uses with the strut he has and he increased the tire size. Pazmany who?
You Tube, the Encyclopedia Brittanica of engineering knowledge.

BJC

Rik-

Well-Known Member
"Asking for a friend" So.... Would a gas shock cure his problem? Does it just need more rake? I read one response it needed more or less weight on YT I believe, well that's not going to work as the plane has to lift off eventually (ideally) but given there is some amount of lift being generated at 40-60 mph (where the shakes seem to occur) lessening the load seems to lead to the shimmy's.

Looks like the entire assembly is shaking. Does it just need a more rigid attachment to the hull? Hell shopping carts shake sometimes and they are full of rake.

pictsidhe

Well-Known Member
No, not even a couple of hours Ross. Some quick numbers suggest under half an hour with properly matched turbos and 300hp at angels two-five, with full fuel... I have a feeling that this is yet another of Peter's clever ideas that he did not do a mathematical sanity check on.

With 10 gallons for a quick pattern flight, he may have some serious structural issues after mere minutes. Aren't the rear walls of the tanks the main spar? The numbers I saw suggest that the intercooler is absorbing 29kW of heat at full power on the ground. I suspect that number is low as it was a very brief test...

Last edited:

Venom

...........the justified criticism of Peter is because he induced people to invest $2.7 million........That's a different case than some guy just trying to design and to build himself a plane....... . Ok, but (playing devils' advocate here) what's that got to do with you? Are you one of the investors? Then step right up, the Microphone is yours. Everyone starts from somewhere and Nothing is learned without trying. Your statement is focused on negativity from a point of view of $$. A good salesman, going out on a limb here (maybe a thing weak one), but if he's a good salesman then more kudo's to the guy as there's been more great businesses to go down the toilet due to bad businessman-ship than good ones succeed despite the bad businessman-ship. I don't know if you remember Jim Bede's escapades from the early seventies, but he got a chunk of my money pullin' the same shenanigans that Peter is. Flyboy is absolutely and precisely correct in his evaluation of this mess. Go build whatever you want, no one cares. But do it with your own money and keep your mouth shut. Having said that, I don't believe Peters extensive and time consuming participation in Youtube has anything to do with some desire on his part to be transparent. One would think the motive is revenue. Last edited: Venom Well-Known Member Moderator Note: Okay, let's make this a little more official:.......as well as your constructive criticism......... Since this is "Official" please allow me an "official" question. What is this..... "PC"? Why on earth does a criticism need to be constructive. Perhaps many readers do not like, appreciate, or want this project or person to succeed. That being the case, maybe a contributor would like to write a destructive criticism intended to harm the project. Why on earth is the owner or moderator of this forum intent on insuring criticism is upbeat and positive? What business is it of yours, provided you are immune from lawsuit? I want to read what people have to say and think RAW. Not what a moderator chooses for me to read. I guess that was three official questions....have at it. Last edited: Rik- Well-Known Member I don't know if you remember Jim Bede's escapades from the early seventies, but he got a chunk of my money pullin' the same shenanigans that Peter is. Flyboy is absolutely and precisely correct in his evaluation of this mess. Go build whatever you want, no one cares. But do it with your own money and keep your mouth shut. Having said that, I don't believe Peters extensive and time consuming participation in Youtube has anything to do with some desire on his part to be transparent. One would think the motive is revenue. What if, if, this guy is merely being transparent and showing his journey of his building his very own fat looking Velocity and nothing more? Everyone is cheering for disaster but not one hater has risked a single$$ of their own on this project so speculation is rampant but facts are elusive as his success to date. More power to the guy. I’ve got nothing in this other than the time on YT watching his progress occasionally. He’s to dry to watch his whole series. What if he gets the wheel problem cured and then the **** thing flies the pattern and lands safely? A lot of members minds will explode if that could actually happen BJC Well-Known Member HBA Supporter What if, if, this guy is merely being transparent and showing his journey of his building his very own fat looking Velocity and nothing more? That is not the case. He is pursuing a commercial venture and has projected / claimed performance and price that are totally unrealistic. Everyone is cheering for disaster but not one hater has risked a single$\$ of their own on this project so speculation is rampant but facts are elusive as his success to date.
Not all people here are cheering for disaster. Lots of facts are clearly evident in his videos. He get high credit for enthusiasm and effort, not so much for engineering and project management. At this stage, most of us are just hoping that no one gets hurt trying to fly the Raptor. (One fact: A highly experienced professional test pilot declined to fly the Raptor.)

More power to the guy. I’ve got nothing in this other than the time on YT watching his progress occasionally. He’s to dry to watch his whole series.

What if he gets the wheel problem cured and then the **** thing flies the pattern and lands safely? A lot of members minds will explode if that could actually happen
That would be a successful first step that would need to be followed by many more. The Bugatti Racer replica had a successful first flight.

BJC

Last edited:

pictsidhe

Well-Known Member
I see that the troll is sucking everyone into a fight again.

He won the first round, lets try not to give him the second, too.

Personally, I dislike scammers. I'm not PC enough to ever pretend that I don't.

flyboy2160

Well-Known Member
...
I want to read what people have to say and think RAW. Not what a moderator chooses for me to read...
Well, the owners of this site don't want that.

I agree with them.

I'm sick of the immature, vicious name calling that dominates too many online forums. I was a moderator on one of the big F1 forums. What a PITA. Almost every day I had to put a stop to supposedly 'technical' discussions that consisted of:
'No, you're an **s**le.'
'You have **it for brains.'

Some of the MOTOGP forums are also like that. Who wants to wade through that garbage?

I'm glad this place is moderated the way it is.

Raptor's Youtube page doesn't seem to be well moderated. Why not just rant there instead of here? The people there seem to be almost all adoring True Believers, so you'd have a lively discussion with them.

Last edited:

BJC

Well-Known Member
HBA Supporter
I read it cover to cover although it wasn't necessary.
They are all the same.
My questions are not answered there, but you know that.
Just because you do not like the answers does not mean that your questions are not answered.

I also know how to use other features of this forum.

Bye.

BJC

Last edited:

Rik-

Well-Known Member
That is not the case. He is pursuing a commercial venture and has projected / claimed performance and price that are totally unrealistic.

Not all people here are cheering for disaster. Lots of facts are clearly evident in his videos. He get high credit for enthusiasm and effort, not so much for engineering and project management. At this stage, most of us are just hoping that no one gets hurt trying to fly the Raptor. (One fact: A highly experienced professional test pilot declined to fly the Raptor.)

That would be a successful first step that would need to be followed by many more. The Bugatti Racer replica had a successful first flight.

BJC
I was wondering if he had approached anyone else to fly the plane and do the shake down work for him. I mean, not everyone is a test pilot and that's certainly a job for one with this project..

Hot Wings

Grumpy Cynic
HBA Supporter
Log Member
I also know how to use other features of this forum.
BJC
It would be nice if the new software would show that there is ignored content without having to click on the "Show Ignored Content" button. Some of the responses would make more sense if we knew they were made about an ignored member's comment.

BJC

Well-Known Member
HBA Supporter
I was wondering if he had approached anyone else to fly the plane and do the shake down work for him. I mean, not everyone is a test pilot and that's certainly a job for one with this project..
AFAIK, he has approached others. (There are some comments about that way back in this thread.) I don’t know if anyone has agreed to fly it.

BJC