Quantcast

Raptor Composite Aircraft

HomeBuiltAirplanes.com

Help Support HomeBuiltAirplanes.com:

Status
Not open for further replies.

Toobuilder

Well-Known Member
HBA Supporter
Log Member
Joined
Jan 19, 2010
Messages
4,920
Location
Mojave, Ca
The "why" of this project is totally obvious to me - but so is a teleporter from Star Trek. The problem here is that the implementation of Raptor as an airplane that will meet these goals is about as realistic as a used refrigerator cardboard box as a teleporter.
 

BBerson

Light Plane Philosopher
HBA Supporter
Joined
Dec 16, 2007
Messages
13,964
Location
Port Townsend WA
If the nosewheel comes off after the mains (or settles) it would be wheelbarrowing and could lose directional control.
 
Last edited:

cheapracer

Well-Known Member
Log Member
Joined
Sep 8, 2013
Messages
6,285
Location
Australian
Somebody doesn't have the foggiest regarding canard aerodynamics.
I admit I had to read it about 5 times, and then some sentences again to get a grasp of what he was saying.

I wonder how much he would have to extend the front leg to alter the AOA to lift without trim. That the trim is near zero now and the front is coming off, as the spring is too weak, it might not be much.

Is that a good or bad idea for this circumstance?
 

TarDevil

Well-Known Member
Joined
Jun 29, 2010
Messages
735
Location
Coastal North Carolina/USA
Latest on PM YT Channel.
What load would the front tire take without bursting.🤔

Raptor Aircraft

17 hours ago
What you need to understand is that while on the gear the nose/canard has about 480lbs on it with me on board. Once the main wing starts to develop lift, because the center of lift is aft of the main gear, a lot more weight transfers onto the nose/canard. In level flight it will be about 1100lbs. The reason I'm trying to get the aircraft to lift off on it's own at 90 knots is because at that speed with a slight nose up the 1100lbs is already on the nose because the main wing is almost taking all the weight off the main gear. If I go slower the nose is much lighter and will come up more readily because there's still so much weight on the main gear. So, given this scenario, once the mains lift off and all the weight is being carried by the wing and canard there's no little to chance of the nose rapidly rotating higher. If anything it's more likely to settle down because it's just not supporting that 1100lbs. By the way, I know it's 1100lbs because I weighed the nose when I had the wings blocked at the center of lift. So, now that you understand what's going on with the weight transfer you should come to the same conclusion that the way I'm bringing the aircraft into ground effect at 90 knots is in fact a reasonable procedure.
Someone tell me how the center of lift is behind the main gear?
Does he, or does he not know that both surfaces are lifting?
 

Hot Wings

Grumpy Cynic
HBA Supporter
Log Member
Joined
Nov 14, 2009
Messages
7,355
Location
Rocky Mountains
"By the way, I know it's 1100lbs because I weighed the nose when I had the wings blocked at the center of lift."
So what is the pitching moment add from the wing and canard at this desired auto lift off speed?

And as type another valid point is raised by another poster.
 

FTEstudent

Member
Joined
Aug 27, 2020
Messages
15
If you guys are dissing the free version, I can't argue because I've never used it.
If you look at the CFD photos on his website, it is SW. Since you haven't used it you may not be familiar but its pretty clear his CFD is all ********. His SR-22 comparison was a model he made, which means it's actually not 100% accurate, compounded by inaccurate software means his numbers are complete garbage.
 

cheapracer

Well-Known Member
Log Member
Joined
Sep 8, 2013
Messages
6,285
Location
Australian
Latest video he has burnt another brake pad and partially glazed the disc, as I mentioned last time, I suspect he has brake drag.

I disagree with his supplier that the runs are causing the issues, there's ample time for the brakes to cool on those long taxis in between runs, as well as the run up to speed itself.

Another possibility is that the axle is flexing under load and forcing the disc against the pad.

Also he is "straightening the rear wheel tracking", people should be aware that this is wrong, toe-in is always desirable for stability, that is the front of the 2 rear wheels point inwards about a degree.
 

Tiger Tim

Well-Known Member
Joined
Apr 26, 2013
Messages
3,401
Location
Thunder Bay
there's ample time for the brakes to cool on those long taxis in between runs
You have more experience than I do with the practical side of this, but since the Raptor has a castering nosewheel he’s almost certainly dragging a brake in taxi just to keep it going straight. That might not be enough to heat it up but it must at least be slowing the cooling of that brake.
 
  • Like
Reactions: BJC

Wild Bill

Well-Known Member
Joined
Dec 11, 2013
Messages
98
Location
Vidalia, GA
Could be some issues leading to excessive wear.. But then again differential braking is going to eat brakes to some extent. On top of that look at those runs he’s making.
He’s probably put 4,000 miles on it since the last set of brakes.
Sending that thing down the runway at 90knots only to turn around and do again and again can’t be good for brakes.
Aircraft at a flight school don’t even see that level of brake abuse.
 

flywheel1935

Well-Known Member
Joined
Nov 1, 2018
Messages
360
Location
Downham Market, Norfolk, UK.
Could be some issues leading to excessive wear.. But then again differential braking is going to eat brakes to some extent. On top of that look at those runs he’s making.
He’s probably put 4,000 miles on it since the last set of brakes.
Sending that thing down the runway at 90knots only to turn around and do again and again can’t be good for brakes.
Aircraft at a flight school don’t even see that level of brake abuse.
I'm sure Wasabi commented on the rudder position/ergonomics. possibly he is 'riding' the brakes as he pedals away at the rudder, would account for the glazing.!!! 🤔
 
Status
Not open for further replies.
Top