Cool New Canard Designs

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flyvulcan

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I don’t think it’s fair to judge this program or it’s participants on the basis of a single quote by John and frankly, I’m a bit disappointed that the thread deteriorated very quickly into attacks on the project and it’s participants.

I know both John and Jeff and they are honest, ethical and extremely hardworking aviation enthusiasts with an amazing skill set between them.

The aircraft that they have under development are exciting products that will help some folks achieve their need for speed.

I also know that both Jeff and John listen to and evaluate the merits of any feedback they get. If any contributors on this forum feel that they have any constructive feedback on any elements of the design or construction of these aircraft, post them here. Jeff will almost certainly be monitoring the thread and he will take them on board.

If your advice or criticism does not come from a background of proven knowledge or experience, I suggest that you simply do not post it and leave the advice to those that have the experience.

Revel Aero has a Facebook page where their progress is regularly updated. You will be able to see there about how their project is progressing. It also demonstrates how they build things which would fascinate many of us on this forum.

For those wondering about their Voodoo twin jet, it is for an Airshow act. Hence the high thrust to weight ratio and the limited endurance.

With the advent of the Subsonex and with other small jets about to come onto the market, there is a push for a new small jet class of air racing for Reno. The Voodoo may well be a candidate for such a class of air racing. Speed wise, it will likely beat the pants off a Subsonex.

For folks wanting an economical but fast single seater, the 60hp HKS powered Talon could be an appealing aircraft. Their proposed range of aircraft cater to most needs and budgets for a single seater.

I for one will be encouraging and supporting Jeff and John in their endeavours because they are honest, they want to do it right, they do listen and they are good at building aircraft.
 

BoKu

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...With 3000N for 1000lbs it seems to me he mistook the newton for lbs...
I work with climbing gear a fair bit, and it is usually rated in kilonewtons (kN). The memory trick I use is that 1 kN is about equivalent to the force applied by the weight of a typical firefighter; about 225 lbs. So for example a carabiner rated for 23 kN has lots of margin when loaded with a single firefighter, and no margin when loaded with 23 firefighters (not that you'd ever ever do that).

Anyhow, since 1000N = 225 lbs, 1N = 0.225 lb and 1lb = 4.44N.

...Another thing is, that the twin jet will be limited to around 15 minutes of autonomy. So main use case seems to be Reno unlimited race...
Jet class, maybe. The unlimiteds are restricted (nice contradiction, eh?) to piston power.

Heading off-topic, one other thing I picked up from working on L39 racers: Jets and recip prop engines are fundamentally different in how they deliver power into the air. Recip props are basically constant power. And since there's a V term in the expression for power, when speed goes down, thrust goes up. So if you scrub off a bit of speed while maneuvering, you can recover it more easily because you have more thrust available. The jets, on the other hand, are basically constant thrust. And when you scrub off a bit of speed maneuvering, you don't have any additional thrust to get going again with. That's why jet class racing is much more rewarding for pilots with good strategy, good lines, and smooth flying. It's also why our wingtips help like they do.
 

pictsidhe

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North Carolina
I don’t think it’s fair to judge this program or it’s participants on the basis of a single quote by John and frankly, I’m a bit disappointed that the thread deteriorated very quickly into attacks on the project and it’s participants.

I know both John and Jeff and they are honest, ethical and extremely hardworking aviation enthusiasts with an amazing skill set between them.

The aircraft that they have under development are exciting products that will help some folks achieve their need for speed.

I also know that both Jeff and John listen to and evaluate the merits of any feedback they get. If any contributors on this forum feel that they have any constructive feedback on any elements of the design or construction of these aircraft, post them here. Jeff will almost certainly be monitoring the thread and he will take them on board.

If your advice or criticism does not come from a background of proven knowledge or experience, I suggest that you simply do not post it and leave the advice to those that have the experience.

Revel Aero has a Facebook page where their progress is regularly updated. You will be able to see there about how their project is progressing. It also demonstrates how they build things which would fascinate many of us on this forum.

For those wondering about their Voodoo twin jet, it is for an Airshow act. Hence the high thrust to weight ratio and the limited endurance.

With the advent of the Subsonex and with other small jets about to come onto the market, there is a push for a new small jet class of air racing for Reno. The Voodoo may well be a candidate for such a class of air racing. Speed wise, it will likely beat the pants off a Subsonex.

For folks wanting an economical but fast single seater, the 60hp HKS powered Talon could be an appealing aircraft. Their proposed range of aircraft cater to most needs and budgets for a single seater.

I for one will be encouraging and supporting Jeff and John in their endeavours because they are honest, they want to do it right, they do listen and they are good at building aircraft.
I can count. But I am still having a hard time designing an aircraft. I am more than a little skeptical of the chances of people who can't count doing so. Being honest and hardworking are not the skills to design a good aircraft.
 

mcrae0104

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It's also why our wingtips help like they do.
I was sitting at HBHQ at OSH on Sunday, sketching out some details I had been ruminating on for the week, when a stranger asked me what I was up to. It led to a great morning's worth of conversation including, among other things, the value of reducing induced drag in a turning fight or a pylon race. So I'm curious, Bob, can you tell us anything about the tradeoffs between increased span (decreased span loading) and wetted area? Do your tips trade approximately the wetted area of the -39's tip tanks for increased span? Seems to me this should be a no-brainer to go with your tips.
 

pictsidhe

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How long is a piece of string?

If your induced drag is higher than your parasitic drag, bigger tips will help. If the other way down, a wing clip will help. Pylon racers alternately bank hard, which increase induced drag, then fly straight and level which cuts it. You need to find the right balance between the two. Gaining afew mph i the corners is worth losing a little on the straight.
Look at all the fun the Formula 1 teams have setting up their cars for each track. They have to balance cornering speed with straight line speed. This is sometimes very obvious, with one car being noticeably quicker on straights than corners and vice versa.
 

Scheny

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Feb 26, 2019
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In case anyone interpreted the low endurance as a negative point, this was not intended. A Bugatti Veyron will burn its tires within 17 minutes at top speed, but it is of no concern, as gasoline will only last for 12 minutes :eek::p

People have different use cases and this plane is very promising for both the pilot who wants to cruise cheap and the Reno fanatics.

Rutan always had a faible for small planes running efficiently. If he would be 30 years younger, this is how his next design would look like.

Good work Jeff, you always impress me. This coming from someone disliking canard.
 

Alan_VA

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Apr 17, 2011
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Bristow, VA
Cute little plane - be interesting to see what the market is.

I was somewhat perturbed, though, that John stated that the twin jet version will accelerate at 3G (which he mentions a few times) with 700 lb. of thrust and an 1100 lb. MGW. Even if EACH of the engines produces 700 lb. of thrust (I don't think that's the case, but lets be generous), then with 1400 lb. of thrust and 1100 lb. of weight, I get 1.27 G acceleration, or (with 700 lb of thrust - more likely) 0.64 G. Either one of these is going to be exciting - hell, even the single jet version, with 350 lb. of thrust, would be exciting - but it's not Spaceship 1's 3 G's. This is a relatively trivial calculation...

Did I miss something?
With SAE units it's very easy to forget to use the gravitational constant to convert 1100 pounds weight (a force) into units of mass (slugs). And then to do the F=ma calc.
1100 lbf / 32.174 = 34.189 slugs
a = F/m
a = 700 lbf / 34.189 slugs
a = 20.474 ft/sec2
a = 0.636 g

Alan
 

Urquiola

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Aug 23, 2013
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90
Location
Madrid, Spain
You may like the article: 'Canards: design with care', by B R A Burns, it appeared in 'Flight International', 1985-02-23. Their whole back issues database is open and free. Salut +
 

TMann

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Aug 15, 2011
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163
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Omaha, NE
Very exciting to have a new entry in the canard arena.
I had heard that they had sold some kits at Oshkosh.
I'd have a hard time putting money down on something that hasn't flown yet.
I think that there have been too many instances of that in the past where dreamers lost their money.

I wish them the best.
 

wsimpso1

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With SAE units it's very easy to forget to use the gravitational constant to convert 1100 pounds weight (a force) into units of mass (slugs). And then to do the F=ma calc.
1100 lbf / 32.174 = 34.189 slugs
a = F/m
a = 700 lbf / 34.189 slugs
a = 20.474 ft/sec2
a = 0.636 g

Alan
Or just divide the weight by the thrust (with both in pounds) to get the max g's that it can accelerate at with a lot less shenanigans. Or divide its weight in Newtons by its thrust in Newtons to do exactly the same thing.
 

AdrianS

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Or just divide the weight by the thrust (with both in pounds) to get the max g's that it can accelerate at with a lot less shenanigans. Or divide its weight in Newtons by its thrust in Newtons to do exactly the same thing.
Pedant alert : there's no such thing as weight in Newtons.

A = F/M
1 g = 9.8 m/s/s

Acceleration (g) = Thrust (N) / {mass (kg) x 9.8}

For back-of-the-envelope estimates, 10 will do :
Accel (g) = thrust (N) / {10 x Weight (kg)}.
 

wsimpso1

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Pedant alert : there's no such thing as weight in Newtons.
I do not know if AdrianS really buys that the complication is needed to understand this or if he is just trying to pull our collective chain...

For those of you open to what is KNOWN:

SI mass is in kilograms. SI force is in N. SI acceleration is in m/s/s. The force generated by a mass under an acceleration is the mass (in kg) times the acceleration (in m/s/s) and is expressed in Newtons. If you are present on the surface of the Earth, things with mass being pulled by gravity have measurable weight which can be measured using the same force sensor calibrated in Newtons.

The fact that your scale is calibrated to show you kg while it sits on Earth does not change this. If we put you on that scale and go fly at different g's, your weight changes but I can tell you for a fact that your mass is not changed by the event, no matter what the scale shows. The scale shows force applied, and its calibration and labeling is immaterial to these things.

One other point - you can not measure mass with a scale unless you know the acceleration being applied to the mass. You can measure the force applied and if you know the acceleration, you can figure out what the mass is. This is why a kilogram of steel weighs 9.8 N when measured statically and in nominal air on the surface of the earth. It is also why a slug of steel weighs about 32 pounds when measured statically and in nominal air on the surface of the Earth.

This stuff of taking something that weighs some weight on Earth and then applying some force to it and having to go back to mass to know what it will do is complicating the process, and was my point in my previous reply.

As to "there is no such thing as weight in Newtons", well, think what you want, but know that Newton is unit of force, which is weight when the mass is under an acceleration such as that provided on Earth's gravity.

Billski
 

BBerson

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The original two seat Rutan VariEze was designed for VW power but had some problems with the VW. This presumably lighter one seater could probably work well with a VW if the pusher engine is properly cooled.
 

Hot Wings

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One other point - you can not measure mass with a scale unless you know the acceleration being applied to the mass.
And this is now how a Kg is now defined - with a Kibble balance. No more need for a chunk of metal to be kept in isolation.

And to keep this HBA related - the Homebuilt version for getting very accurate mass measurements of our parts:

https://www.nist.gov/si-redefinition/nist-do-it-yourself-kibble-balance-made-lego-bricks

If "Weight is the enemy" then it doesn't matter how much mass we use to build our planes, we just need to fly higher. :oops::p
 
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