# Raptor Composite Aircraft

### Help Support Homebuilt Aircraft & Kit Plane Forum:

Status
Not open for further replies.

#### dodgemich

##### New Member
How would you see flex if the image stabilization is distorting the footage?

That would seem to be a contradiction, no? Or is there some way to tell when the camera is jumping as opposed to the airplane?

Edit: for instance right here [10:12] on the ground roll, we see that the wing bars on the PFD are perfectly still, but the wing view is jumping up and down. What's going on there?

Edit 2: Also here, one minute later at 11:12. After it settles down from the oscillation, we see the underwing shot showing up and down motion while the attitude indicator is [momentarily] still.
FWIW, I don't think he got his PFD view and wing camera in sync - but not a giant surprise.

If you look at the final landing, the PFD view is about 2 seconds ahead of the wing camera based on the landing jolts.
Code:
12:45 = first bump on the panel view
12:47 = first touchdown

12:48 = more violent landing in panel view
12:50 = more violent landing
As far as image stabilization goes, the typical GoPro seems to use a combination of internal gyros with some image-based processing - here's an example of a well-mounted GoPro out the front, no vibration, but it's doing stabilization from the manuevers to cause the cowling to wander about - at about :20 you can see the edge of the glareshield pop in...you can tell that he's getting something similar as the plane porpoises around, albeit more exaggerated due to the more exaggerated motions:
:

#### Erik Snyman

##### Well-Known Member
No, I dont think so. We still have a standard to adhere to, dont you know....

#### Toobuilder

##### Well-Known Member
HBA Supporter
Log Member
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.
Within the field of formal flight test there exists a great deal of self study and reflection so that the same mistakes are not repeated over and over. If you work for a company large enough to have a flight department and/or belong to SFTE or SETP like I do, then you will be familliar with the quarterly safety meetings - an opportunity to spend 8 hours hearing guest speakers dissect well known accidents in an attempt to show just how dumb humans are in the grand scheme of things. Normally, these case studies come about after a fatal or landmark accident, but in the case of the Raptor saga - as well documented as it is - one can only cringe at the similarities of the decisions being made to the past accidents.

Laypeople consider this "hating" on Peter, but for many of us, we are quite literally "trained" to recognize and avoid the red flags his behavior throws up. We really can't help it. Much of what he does is as obviously wrong as watching a toddler play with a loaded gun. You just know how its going to end, but there is no reasoning with the victim beforehand.

#### pictsidhe

##### Well-Known Member
With all the talk about how much the raptor is wallowing around or the wings flexing as opposed to the camera stabilization making it look worse than it is, there must be someone here that has the skills and video editing software to re-stabilize the video in relation to say the horizon or the fuselage. If that can be done it would show more clearly just how much wing flexing or porpoising is happening?

#### Steve C

##### Well-Known Member
I don't see excessive wing flex either.

This thing has enough much more obvious problems.

##### Well-Known Member
We do have access to unstabised video, not the flight, but Elliot Seguin's videos includes the taxi tests, engine start, gear swing, there isn't a lot of flex at all in the wing, which means its flutter (or some other fun vibrational mode) or camera artifacts.

#### Victor Bravo

##### Well-Known Member
HBA Supporter
I believe that most of the original (fiberglass construction) Rutan canards have a fair bit of wing flex. The experienced canard people here can verify or refute that. My couple of passenger rides in a Long-EZ convinced me there was a little wing flex (and canard flex) and it was a perfetly good thing to have, assuming that the flex and twist had been accounted for by Rutan in the design engineering process.

(Rutan's composites mentor Fred Jiran - a larger than life character BTW but one hell of a craftsman- was an experienced composite sailplane technician, so it is highly likely that Rutan was told early on that some controlled amount of flex is a good thing).

I bellieve most composite airplanes have a little flex, unless designed specifically to the contrary (Extra 300 or all carbon acro airplanes). Wing flex, a few inches up or down, is probably not a bad thing in the Raptor, because it smooths our or absorbs some of the sharp edge gust loads. If the B-52's aluminum wings can go up and down 15 or 18 feet...

Last edited:

#### Andy_RR

##### Well-Known Member
A good friend of mine, showing me off his access to a Grob Egrett, grabbed the wingtip and tried to wobble it hard. It was unbelievably stiff for something with a 33m wingspan! The next demo was a Super Dimona which was jelly (translation: Jello) by comparison!

#### donjohnston

##### Well-Known Member
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.
The current Velocity kit (since about 2015) has no cables to the ailerons. It's all push rods. Only cable controls are to the rudders.

#### donjohnston

##### Well-Known Member
They do not have control and behaviour problems if you build them to the plans. The plans include vortillons. Rutan ships and the Cozy/Velocity/other derivatives all have vortillons in the plans to make them behave well. Build to plans and they fly fine, skip the vortillons, move the elevator hinges, omit the lower winglets, etc, and you will not get the whole set of known good flying characteristics.
My Velocity doesn't have votrilons and flies just fine. I noticed no difference in flight behavior with or without them.

#### rv6ejguy

##### Well-Known Member
HBA Supporter
My Velocity doesn't have votrilons and flies just fine. I noticed no difference in flight behavior with or without them.
Don, curious to know if your Velocity wing flexes like we see on Raptor when Peter is shaking it?

#### Richard Schubert

##### Well-Known Member
but for many of us, we are quite literally "trained" to recognize and avoid the red flags his behavior throws up.
I was walking through a parking lot with a friend who's main job was inspecting compressor blades for USAIR. We were talking and suddenly he stopped and pointed at a car about 8 feet away and said, "Look at that!"

We walked over, there was a hairline crack in the aluminum wheel radiating out from a lug hole toward the rim.
To an ignorant savage like me, it might as well had been magic.

#### canardlover

##### Well-Known Member
My Velocity doesn't have votrilons and flies just fine. I noticed no difference in flight behavior with or without them.
The purpose of the addition of vortilons was to excite the air flowing over the ailerons at slower speeds/ higher alpha. That is when spanwise flow increases, compromising airflow over the ailerons. This is supported by their actual placement at the leading edge within the confines of the spanwise location of the ailerons. They generate vertices to help keep flow attached and enhance aileron authority at slower speeds. They likely produce little effect at cruise speeds where spanwise flow is non existent or minimal at best. The underwing fences I added to the model were required to control spanwise flow wrapping around the radiused transition( bad idea) and up the vertical thereby disturbing flow over the verticals/ winglets reducing their effective area and stabilizing effect. They proved very effective in addressing the dutch roll problem discovered in the model. But one test flight does not a full evaluation make!! All the original canards had winglet extensions below the wings lower surface proving a tip plate effect and mitigating high pressure airflow from wrapping around wingtip. Many people have done away with them for aesthetic benefit. I doubt anyone has performed any quantitative/ qualitative comparative behavioral analysis. Marc Zeitlin may be able to comment more on this matter as he is more involved in the VE,LE,Berkut,Cozy fraternity. Velocity has some examples with no lower winglets but ultimately reverted back to incorporating them shortly after we completed the execution of the XL model, possibly due to influences from the longer /wider fuselage. The radiused transitions may look cool on airliners ,etc , however in those applications the winglets are not required to unduce yaw/spiral stability.

Last edited:

#### Jeff Liot

##### Member
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.
Thanks Victor for bringing this up. I personally felt ashamed that my fellow builders would find nothing but fault in a first flight that Peter spent years and years working towards. Sad.
Jeff Liot

#### rv6ejguy

##### Well-Known Member
HBA Supporter
Thanks Victor for bringing this up. I personally felt ashamed that my fellow builders would find nothing but fault in a first flight that Peter spent years and years working towards. Sad.
Jeff Liot
Many of us sent congrats to Peter for his accomplishment (I did) and I believe he also did a good job getting if down in one piece despite his lack of familiarity with canards however, my praise stops there. This design is dangerous and untenable on so many levels as has been well documented here. I'll go out on a limb and say that this aircraft will never complete 100 hours of flight without a big mishap and it will require hundreds of hours to prove itself safe given so many unknowns designed by a guy with no background in any of the required disciplines..

This wasn't intended as a one-off for personal use for Peter, it was designed to go into kit production for hundreds of deposit holders. Big difference.

#### pictsidhe

##### Well-Known Member
Something weird that I like doing on airliners is watching the wings flex and bounce. They are most certainly not rigid.
The bendiest by far was a 787. It was also by far the smoothest flight I've ever had. My mid Atlantic yoga routine had previously only reached tree pose. On the 787, I worked through to warrior II and was thinking about trying half moon when a flight attendant busted me. Yep, very smooth flight!

#### poormansairforce

##### Well-Known Member
The underwing fences I added to the model were required to control spanwise flow wrapping around the radiused transition( bad idea) and up the vertical thereby disturbing flow over the verticals/ winglets reducing their effective area and stabilizing effect. They proved very effective in addressing the dutch roll problem discovered in the model. But one test flight does not a full evaluation make!!
Wait, Peter actually addressed this in the model flying video that it seemed to control that transition problem. So why did he not include that on the full scale?

#### Steve C

##### Well-Known Member
Sorry Jeff, but there wasn't much but fault to find. That flight was insanely risky knowing what we knew from previous tests.

The part where he seems to have no friends is sad. Most folks I've run into at the airport have been very friendly. I'd have to assume he isn't.

Status
Not open for further replies.