Raptor Composite Aircraft

Homebuilt Aircraft & Kit Plane Forum

Help Support Homebuilt Aircraft & Kit Plane Forum:

Status
Not open for further replies.

Scheny

Well-Known Member
Joined
Feb 26, 2019
Messages
295
Location
Vienna, Austria
The bad bearing seems to be the cause for the wobbling along the longitudinal axis we noticed for some time now.

The scary shaking definitely was caused by the unbalanced ailerons. They amplified the wings going up and down, so it was like a pilot induced oscillation, just worse, as it happens without any input. I NEVER have seen a plane oscillating about the longitudinal axis!!!

What scares me, is that Peter obviously thought that someone only get balanced for easing control forces. I mean come on, he is a flight instructor and this is basic knowledge.

The first lesson I had in a plane was a walk around and they said "if a counterbalance is missing, don't get in, as it will flutter for sure".
 

Scheny

Well-Known Member
Joined
Feb 26, 2019
Messages
295
Location
Vienna, Austria
Wing going up, aileron going down. Motion is amplified. Wing going up, aileron going down. Motion gets amplified again.

With the ailerons weighing about 10lbs and the plane having this short side stick, there is no chance to stop this by pilot input...

Unbalanced = death trap
 

Andy_RR

Well-Known Member
Joined
Sep 29, 2009
Messages
308
Location
Melbourne, Australia
Unbalanced control surfaces would probably work OK if the control linkages were stiff enough - especially at the airspeeds we're talking about here. I think it's a compounding problem.

Peter is making this much harder than it needs to be for want of some real engineering. All of this is foreseeable from the CAD workstation...
 

berridos

Well-Known Member
Joined
Oct 10, 2009
Messages
1,165
Location
madrid
One has to admit that he is **** sincere. I would have buried that video in the garden in 2 meters depth and instead state i had the flu and couldnt publish a video this week. If he stays as disciplined with his transparency effort, we could end up watching his body in the news teared in pieces after the crash.
 
Last edited:

TarDevil

Well-Known Member
Joined
Jun 29, 2010
Messages
1,066
Location
Coastal North Carolina/USA
Is it known who did the aerodynamic design? The structural design?

Is it known whether or not any professional test pilot has agreed to fly the Raptor?


BJC
Peter has stated that Justin Gillen and Elliott Seguin are "on board" and waiting for Peter to get the plane "dialed in." I've never seen any commitments to actually fly this thing.

You guys know these two pros. They don't do stupid.
 

cheapracer

Well-Known Member
Log Member
Joined
Sep 8, 2013
Messages
6,421
Location
Australian
Having watched Peters latest video 129 'buyers' have asked for there deposits to be returned, and one has just be sectioned under the 'mental health act' !!!
No one is going to argue with that prediction there Nostradamus, I feel you left out a word that starts with "law" and ends with "suits" in there somewhere though ...
 

pictsidhe

Well-Known Member
Joined
Jul 15, 2014
Messages
8,815
Location
North Carolina
The 0.6Hz-ish mode could be one natural frequency of the ailerons. Considering how floppy they seem to be, that doesn't seem unreasonable. Unless you are considering the ability to fly safely. Balancing them will lower that a bit.

We're probably going to have to wait for the NTSB report for good details. If it has more than a runway excursion, this project is high enough profile to be given some effort by the NTSB to discourage a 'Raptor 2'.
 

flywheel1935

Well-Known Member
Joined
Nov 1, 2018
Messages
555
Location
Downham Market, Norfolk, Great Britain.
On a more serious note, Peter said he had a failure on a HYSOL bonded part ??? the part looked like Nylon ? would you normally epoxy a part in place, using peel ply, then bond around said part with more carbon ??? I'm using HYSOL to bond my alloy framedIMG_1958.JPG fuselage together
 
Joined
Aug 15, 2013
Messages
3,056
Location
Western US
On a more serious note, Peter said he had a failure on a HYSOL bonded part ???
The blue color suggests that it's Hysol EA9360, which we use in a couple places on the L-39 jet wingtips. It's strong stuff.

...the part looked like Nylon ?...
He says in the commentary that it's FR-4, which is another name for Garolite G10, and indeed it does look like that material.

Garolite is a good material for this; we use it for a lot of hardpoints in our composite gliders and other assemblies. However, this piece has a lot less bond area than I would have used unreinforced. In my shop, we would either have used a much larger piece of Garolite with more bond area, or we would have overlaid it with several plies of fiberglass or carbon fiber reinforcement. We probably would have done both. For example, for the landing gear trunnions in our glider, a very similar application to Raptor's, we use a ~2.5" disk of 3/8" thick G10 with a ~1.13" hole in the center for the bronze bushing, and subsequently apply five plies of 7725 to spread the load out over a circle of ~6" diameter. Four such anchors support the welded steel yoke and oleo struts for the monowheel undercarriage.

Looking at that big spherical bearing, one of eight in Raptor's undercarriage system, you can get a sense of why Raptor is so much overweight. We would have used bronze bushings installed with special alignment fixtures to ensure colinearity. That would have had the same reaction capacity with much less mass.
 
Last edited:
Status
Not open for further replies.
Top