Raptor Composite Aircraft

Homebuilt Aircraft & Kit Plane Forum

Help Support Homebuilt Aircraft & Kit Plane Forum:

Status
Not open for further replies.

pictsidhe

Well-Known Member
Joined
Jul 15, 2014
Messages
8,815
Location
North Carolina
Low-Pressure <250 PSI, uses lighter, less stressed components, it's easier to install, service, and reliable.
I would submit the cable pulley system installed, re-engineered, modified, and then jerry-rigged is a cluster of epic scale; If the engine does not fail in flight, it will be a control system failure, that brings the bird down. IMHO
You haven't worked on servo hydraulics much, have you?
 

cheapracer

Well-Known Member
Joined
Sep 8, 2013
Messages
6,421
Location
Australian
Actually. I believe that there is a very short pushrod on to the aileron from the last pulley.

You mean to the rudders? Kind of difficult to run push rods out to the winglets.

No, ailerons.

I didn't actually notice it had pushrods from the wing roots to the ailerons, I will have to upgrade the system rating from "horrific" to just "terrible" now.
 

rv6ejguy

Well-Known Member
Supporting Member
Joined
Jun 26, 2012
Messages
4,913
Location
Calgary, Alberta, Canada
I think the whole thing has been thrashed to death now. As Marc said, there are way too many major items to address with simple modifications and fixes. This prototype is so far from being a viable basis for kit production that a second aircraft would have to be built using the lessons learned. Maybe some flight testing of this one could reveal some useful info on flight characteristics but only if the engine could be made reliable. That in itself is a huge task and expense and the stability and control systems are big question marks even then, to exploring the envelope further.

The nail was in the coffin when this airplane tipped the scales at something like 1000-1400 pounds more than comparable, already flying aircraft. Raptor weighs almost as much as TWO RV-10s.

This project is out of money and out of time on its current path.
 
Last edited:

pictsidhe

Well-Known Member
Joined
Jul 15, 2014
Messages
8,815
Location
North Carolina
No, ailerons.

I didn't actually notice it had pushrods from the wing roots to the ailerons, I will have to upgrade the system rating from "horrific" to just "terrible" now.
Aileron cables go out to the ailerons. There is a short pushrod linking them to the ailerons.
Nothing wrong with a well designed cable system. Worked just fine on faster, heavier WWII stuff. Even many of the bombers were manual cable controlled back then. All the fighters were.
 

pictsidhe

Well-Known Member
Joined
Jul 15, 2014
Messages
8,815
Location
North Carolina
Never. A few years back, I was involved in a project in a class 1 enviroment. The only viable safe solution was a manual LP-hydraulic system; I still recieve op reports to this day.
Servo hydraulics are my day job.
So many ways for them to fail. And, they do. You'd need a redundant system. It will not be light, or simple. Primary control failure usually results in loss of control.

Many countries won't permit single circuit hydraulically controlled planes to fly any more. That includes USA. Perhaps E-AB is not included. Do you really think Peter could do something that the big boys have found to be unsafe?

If I absolutely had to not use a mechanical link, I'd prefer a pneumatic system. Leaks are less serious there.
 
Last edited:

Wanttaja

Well-Known Member
Joined
Sep 15, 2013
Messages
2,259
Location
Seattle, WA
It looks like by now, some sort of vibration damper mount would be a standard included item with action cams.
We used to make our own for vehicles. They were a pain, and bulky, but a must have. No jelly effect and a fixed camera perspective.
They do make them, for about $150 or so. The problem is, the cameras themselves are so light that they don't have any inertia.

I bought such a mount (steel plates, gel pads to isolate from the airframe) but it didn't help, in my case. Still too much engine vibration coming through.

Ron Wanttaja
 

cblink.007

Well-Known Member
Supporting Member
Joined
Jul 7, 2014
Messages
988
Location
K2W6, Maryland, USA
I've made some sharp-tongued comments on this thread and joined others in questioning Peter's thought process. But one thing in that "first flight" video just broke my heart for the guy. He had completed a first flight on a brand new airplane, one with a lot of wonky stuff on it, managed to control the airplane even despite some obvious aero and/or elastic issues, and plenty of wonky engine issues. He did it pretty successfully, and he didn't scratch the airplane.... and there was nobody there to pat him on the back, hand him a beer, congratulate him, or be happy for him. That's really sad, as a separate issue from whatever is wrong with his airplane or wrong with him as an airplane builder.
Excellent point! I was actually thinking the exact same thing. Nobody else is there. In any of these videos. No crew, no spouse, not even a passerby to offer a handshake or a high five.

If anything, it eats at the guy big time. Affirmation helps ease pain if anything, even if the event was, for all intents and purposes, all 50 shades of f'ed up and a complete failure. I once brought a severely malfunctioning Osprey back to base during a flight control software test gone badly awry, and our FTEs telling us that we did good helped keep me going as an XP, because at the moment, I was so shaken up I considered walking away from experimental test.

A first flight, no matter what the design, is a BIG DEAL. If the bird is your own design, the successful completion of that first flight, ie getting back on deck in one piece, deserves to be recognized as a milestone achievement, something few (all things considered) can ever say they achieved. I cannot lay claim to flying my own design yet, so I must give credit where due.

Although a fierce critic of his aircraft and techniques, I won't lie; my engineering group did send a congratulatory e-mail to PM as a matter of basic professional decorum.

But now, he has ALOT of work ahead of him, no matter what his next course of action is.
 
Last edited:

Doggzilla

Well-Known Member
Joined
Jun 2, 2013
Messages
2,352
Location
Everywhere USA
Servo hydraulics are my day job.
So many ways for them to fail. And, they do. You'd need a redundant system. It will not be light, or simple. Primary control failure usually results in loss of control.

Many countries won't permit single circuit hydraulically controlled planes to fly any more. That includes USA. Perhaps E-AB is not included. Do you really think Peter could do something that the big boys have found to be unsafe?

If I absolutely had to not use a mechanical link, I'd prefer a pneumatic system. Leaks are less serious there.

The great thing about automotive engines is that they get free vacuum boost. Master cylinders are great stuff. Reliable, light, and redundant.

Since most tech trickles down and not up in the aerospace industry they never became common. But they are perfect for small aircraft with piston engines.
 

Doggzilla

Well-Known Member
Joined
Jun 2, 2013
Messages
2,352
Location
Everywhere USA
Yeah, that was a surprise that he didn't just reduce the number of vortilons from what worked on the model, he eliminated them entirely. They're easy to make, you can just tape them on with VHB, and they help the Rutan canards a lot. It seems like a no-brainer to start with them on and reduce or eliminate them in testing.

But the experts here say there are no control problems with Rutans. How can they need Vortilons if they don't have control problems?
 

Tiger Tim

Well-Known Member
Joined
Apr 26, 2013
Messages
5,055
Location
Thunder Bay
Nobody else is there. In any of these videos. No crew, no spouse, not even a passerby to offer a handshake or a high five.
It’s possible that it’s all a part of the hero story being presented. Don’t forget who edits the videos. Timothy Treadwell did the same thing when he lived with the grizzly bears. Maybe Werner Herzog will some day give us a Raptor documentary.
 

cblink.007

Well-Known Member
Supporting Member
Joined
Jul 7, 2014
Messages
988
Location
K2W6, Maryland, USA
It’s possible that it’s all a part of the hero story being presented.
It may be true, but in this community, that is awful optics, straight up, especially given that this is a high profile, highly promoted project intended for production.

A first flight is a big deal, no matter what, and the least he should have done was have some congratulatory coverage, especially at the level of exposure he has made for himself on the interwebs...and especially since this first flight was in fact intentional.

PM should have known better. Or maybe he did, and did not want to hype it up because he knows this thing very likely has some terminal power and aero flaws.

Like I say, congrats on the first flight...but he is in a potentially serious pickle now. He knows he has hyped himself up and into a position where, despite that he has something of substance, that thing of substance cannot deliver the goods promised. I wish him the best of luck, because I am hard-pressed to see a scenario where this ends well. I think we all want to be wrong about this!
 
Last edited:

pictsidhe

Well-Known Member
Joined
Jul 15, 2014
Messages
8,815
Location
North Carolina
It may be true, but in this community, that is awful optics, straight up, especially given that this is a high profile, highly promoted project intended for production.

A first flight is a big deal, no matter what, and the least he should have done was have some congratulatory coverage, especially at the level of exposure he has made for himself on the interwebs...and especially since this first flight was in fact intentional.

PM should have known better. Or maybe he did, and did not want to hype it up because he knows this thing very likely has some terminal power and aero flaws.

Like I say, congrats on the first flight...but he is in a serious pickle now.
Yes, a few people to slap him on the back and share a bottle of wine or a few beers with back at the hangar was noticeable by it's absence.
 

proppastie

Well-Known Member
Supporting Member
Joined
Feb 19, 2012
Messages
5,793
Location
NJ
But the "process" of flight test and project management displayed here is pure gold from a HF study perspective.
A field I am not familiar with, unless you are talking about control placement, seat comfort etc.......however from a design standpoint (my field) I like to say, "it all depends on the guy" There is good design (management, procedures etc.) and bad, and usually it is because of the guy in charge, the designer/engineer or the project manager. There certainly is a lot of material here but if PM were to attend your summit I wounder if it would do hm any good.
 

Doggzilla

Well-Known Member
Joined
Jun 2, 2013
Messages
2,352
Location
Everywhere USA
Perhaps he flew alone because he did not want the distraction of a crowd.

Or perhaps he was aware of how many aircraft kill their creators on first flight and didn’t want his body dumped on the runway in front of his friends and family like the test pilot of the Kasperwing.

Regardless, it’s an odd thing to get so bent out of shape about.
 
Status
Not open for further replies.
Top