Cozy iv questions

[Hans S]

I've been lurking around the different forums for awhile and am about to buy some plans for the Cozy IV. I have a few questions on mods I would like to do and am looking for some advice.

 

1. Removable wings. I want to be able to trailer it home for maint. and when I won't be flying for awhile. I also am cheap and don't want to have to rent hangar or tarmac space, I'd rather the money pay for gas. Has anyone modified one so that the strakes are within, say 8-10ft? I'm thinking maybe having half the strake built as part of the wing instead. Not sure about the control surface linkages. I'm also thinking having the wings and strakes completely remove from the fuselage. Not sure where I'd relocate the fuel as the wings would be real heavy to move around full of fuel.

 

2. 4" wider fuselage. Not as much as a velocity, but with a little more room.

 

3. I'll be using a 13B or 20B. Either way they'll be turboed. Appr. 300hp

 

4. I want to raise the prop hub, either through a gear box or raising the motor so that shorter gear can be used. On the ground I want to put the bottom of the fuselage 6-8 inches from the ground. I'm also thinking of a osprey type mount so that the engine and cowl are way up. This is kind of pre-planning to have the prop way out of the way for grass/gravel landings, I realize that the front and rear gear will need to be beefier.

 

5. BSR, this will incorporate into a wishbone type of deal between the front an back seats, with the actual canister residing behind the back seat head rest.

 

6. removable wing tanks, ala baggage pods. I'm not sure how much weight those pods can carry though.

 

I realize some of this isn't probably isn't feasible, but there isn't a plane out there that has what I want. The Defiant would be my first choice, but it is next to impossible to find much builder info on it. I also hear it takes ALOT longer to build, though I don't understand why, the extra motor can't add that much complexity. As my wife and I plan on trips across the atlantic when the kids grow up and go to college, I'd like the extra engine for piece of mind.

[Phil Kriley]

I think you'd be further ahead designing your own plane. Most of the modifications you are suggesting are not practical. For example, the plane is not designed for trailering - you have a canard out front that is wider than the strakes. Yes, it CAN be removed, but it's not worth the trouble to do so even once a year. Ditto removing the wings. You want to raise the engine up on a pod and have the fuselage bottom 6-8 inches off the ground? That's not a modification - that's re-design, IMHO. If you don't think there is enough builder support out there for a Defiant - where do you think you will find support for the level of complexity you are talking about?

 

And if you want to fly the Atlantic to visit your kids, I suggest flying commercial - it will be a lot less expensive and a lot safer. Really.

 

Good luck!

[Jon Matcho]

Hans, first, welcome to the forum! Ask whatever questions you like and propose whatever is on your mind.

 

Second, put on your suit of critical protection. Even the smallest ideas tend to get criticized, and I always feel that's a great way to qualify them.

 

Third, your modifications are so drastic that I had to move your thread to this area. Sorry, but if you accomplished all those mods, not even YOU would call the final aircraft a Cozy or a Defiant.

 

Again, welcome, and enjoy!

[Hans S]

It was more of a "what if" type of thing.

 

In the end, I'll probably keep it to just the 4" wider and the engine change. I still might beef up the strakes so that some fuel pods can be put on, on the other hand, sitting in a car more than four hours makes me bonky, so I'll be coming down anyway.

 

I still would like to figure out how to trailer it though, I'd rather not have to deal with the rental cost.

 

And I still really like the defiant, it would actually suite my purposes for what I think I want (not actually what I need)

[Hans S]

Oh and the BSR. Wife says it's gonna have one, period!

[Jon Matcho]

I still would like to figure out how to trailer it though, I'd rather not have to deal with the rental cost.

 

And I still really like the defiant, it would actually suite my purposes for what I think I want (not actually what I need)

Two ends of the spectrum, if this armchairish builder says so himself. Maybe start thinking about sharing a hangar somehow.

 

Fred Jiran created removable wings for a VariEze (very small) -- maybe it was a Long-EZ -- and there are some pictures out there. Search for 'Jiran Wings'. However, easily removable wings and 4-place twin-engine transcontinental monster represent a very unique mission requirement. Forget doing this where the fuel tanks come off with the wings (the main spar is the determining factor in the width, which is mounted to the fuselage).

 

You need to put your thoughts humbly through the wringer and come to terms with what is genuinely a possible platform. Yes, it's easy to throw tomatoes, but you've put out a rather large barn door to aim at. Maybe it's just that "you can't have your cake and eat it too"?

[Cozy Girrrl]

Oh and the BSR. Wife says it's gonna have one, period!

The BSR is ideal for a conventional planform aircraft. The harness is attached to the spar to take the shock loads as the chute opens.

I talked extensively with one of their engineers and we concluded that unless the airframe of a canard is built specifically for the loading when the chute opens, the forward bridle of the harness would most likely bring the canard and instrument panel through the upper torso of the occupants. Or just peal the longerons off the side of the fuselage.

Until the chute has halted the forward movement of the aircraft, 100% of the load is on the forward bridle stays. When the aircraft is decending vertically it is finally hanging by the rest of the harness and the rear harness finally supports the majority of the load.

I can see the Cirrus having a key safety factor if one wants to fly at night in a single engine aircraft, otherwise I feel having an "Easy Button" attracts a portion of the population that should never have flown in the first place if that is what finally put them over the edge towards feeling comfortable flying in a small plane. They'll push it at the first sign of distress.

I am not saying this is your case, just an observation about human nature. I do not feel people should fly if it is contingent on having an easy button to get them out of a sticky situation rather than having the training, practice and confidence to work through it.

Regards, Chrissi

[Hans S]

The BSR would be added during construction and hooked differently than just for to aft. The roll over bar I'm going to put in just behind the pilot seat will wrap around the fuselag. It isn't a fix incase "crap I ran out of gas" more of a "didn't we used to have more wing on that side"? I've read the newsletters of the corrosion that can happen with the aluminum in some of them if they weren't treated correctly, and I'm not saying that will happen. It was mainly thought of as a definate last ditch effort. Me with a chute on my back won't fit in the seat, not that I could get the canopy open anyway. It also is what my wife says is going to be there if our kids are going to be in it.

[Phil Kriley]

One more thought on the parachute - you've said that you want to avoid expense by trailering your plane rather than hangaring it, but you want to install a parachute. What you need to look at is the COST of the parachute - not just initially but over time. They must be re-packed periodically. You may want to do some research into that. I think you will find it to be prohibitively expensive, assuming that you could even find one that would suit the Cozy/Defiant. Good luck!

[Marc Zeitlin]

Oh and the BSR. Wife says it's gonna have one, period!

The company is "Ballistic Recovery Systems". It's "BRS", not "BSR".

 

BSR, in the context of parachutes, stands for "Basic Safety Requirements".

 

Since the Cirrus uses the chute at it's primary spin recovery methodology, and canards don't spin (nor have structural failures not caused by the pilot doing something exceptionally stupid, either in the build or during flight) Adding 60 lb. of weight to every flight to mitigate a contingency that occurs 10E-6 of the time seems counterproductive to me.

[Phil Kriley]

The company is "Ballistic Recovery Systems". It's "BRS", not "BSR".

 

BSR, in the context of parachutes, stands for "Basic Safety Requirements".

 

Since the Cirrus uses the chute at it's primary spin recovery methodology, and canards don't spin (nor have structural failures not caused by the pilot doing something exceptionally stupid, either in the build or during flight) Adding 60 lb. of weight to every flight to mitigate a contingency that occurs 10E-6 of the time seems counterproductive to me.

Now, if he can just convince his wife...

[TMann]

Buy one (a parachute) you can wear. I don't think BRS will sell you one for a Cozy and if you try to do it under the table, they won't repack it when it comes time. (parachutes need to be unpacked, inspected and repacked periodically.)

 

The best approach is to fly high and keep a field available. With an engine out you can still go a long way.

 

Also, the rotary is a very simple engine solution, so why complicate the benign failure rate with a turbo. You can get 300 hp out of a 20B without it.

 

I would say that right now the biggest obstacle in your way is all that 'blue sky' between you and your set of plans.

[Hans S]

the turbo adds more hp/lb than any other mod. It will give sea level performance at higher altitude. I've done custum turbo systems on cars and motorcycles, so for me, they are not complicated.

 

the BRS was used like "crescent" wrench, just a generic term. Though, I don't know if there is another company that sells them. Anyway, maybe we can do without. The wife and I can talk about it.

[chasingmars]

I've been lurking around the different forums for awhile and am about to buy some plans for the Cozy IV. I have a few questions on mods I would like to do and am looking for some advice.

Hi Hans... As you've already found out, your ideas, while potentially interesting from the perspective of a clean sheet of paper, are problematic as modifications. I thought I'd throw in my two cent, and try to add something constructive by adding a bit to Why they aren't likely to be successful. Bear in mind I'm only on chapter seven myself, so, take with salt.

 

1. Removable wings. I want to be able to trailer it home for maint. and when I won't be flying for awhile. I also am cheap and don't want to have to rent hangar or tarmac space

If you're trailering it all the time, well, the road is a harsher environment than a taxiway or the air, think about the ding you get when a stone gets thrown up on your windsheild, if it happens to the plane, hopefully you notice on your preflight! I guess you can always wrap it up in a quilted cover for trips or such.

 

(edit: I did some musing on structural weight, but then on re-reading it didn't make much sense to me, so removed it) long and short is that easy trailering involves a *lot* more than a shorter main spar.

 

2. 4" wider fuselage. Not as much as a velocity, but with a little more room.

Fuselage widening has been discussed to death, probably with more heat than light, but, at the end of the day, a fuselage, esp a boxy one like a Cozy, generates lift, and in a substantially different way than the wing. More significantly, there are, I think anyhow, easier ways of getting elbow room.

 

4. I want to raise the prop hub, either through a gear box or raising the motor so that shorter gear can be used. On the ground I want to put the bottom of the fuselage 6-8 inches from the ground.

Why? It won't really help for grass/gravel, and changing your thrust line will have very significant effects on handling. Moreover, remember these aircraft graze forward for ground stability when parked. With short mains, you'll worsen what is a livable design compromise. If you are thinking that by putting in a take off attitude you can move the short main back to avoid tip back, well, then you'll always be landing on your nosewheel. which is not good.

 

I'm also thinking of a osprey type mount so that the engine and cowl are way up.

At high power settings, the moment arm that the high mount engine produces will mean that the canard will have to carry more of a share of the lift and you can't offset this at the low end without risking deep stall, so at high cruise power you will kill efficiency of the wing (an issue canards already have and much of why they don't see as much real world benefit of their "all surfaces lifting" planform). By forcing the canard to work significantly harder than the main wing to counteract engine couple, you raise the induced drag (it goes to the square of the lift coefficient) and hurt performance.

 

6. removable wing tanks, ala baggage pods. I'm not sure how much weight those pods can carry though.

Only needed if you have no strake tanks, I think the plane can already go further than most bladders. But, I suppose ferry tanks are probably the easiest of the mods you'd proposed.

 

but there isn't a plane out there that has what I want.

Well, that's probably because airplanes are compromises by their inherent nature. The question is, is the Cozy the right compromise for you? If you have a compromise in mind that doesn't have an example, you can either design it, or accept the limitations of a design that's good enough. But I'd caution you as others have, the scope of what you proposed, well, to be honest, a clean sheet design would probably be easier and need the same level of knowledge and skillset.

[chasingmars]

the turbo adds more hp/lb than any other mod. It will give sea level performance at higher altitude. I've done custum turbo systems on cars and motorcycles, so for me, they are not complicated.

I'd suggest you take a read of John Slade's site, you will certainly enjoy it if you want to use a turbo rotary. He's blazing the trail. In some cases, with bits of blown turbos. Car and motorcycles may not give you adequate background depending on how well you can extrapolate that the what happens when the atmosphere gets tenuously thin and what that does to pressure ratios, and the fact that as you climb, turbine output rises while compresser absorbed power falls.

[Nathan Gifford]

BRS has its own problems. I think Marc, et al, have said that safety is a series of hopefully thoughtful tradeoffs. In the case of BRS you need to evaluate the cost of BRS vs something else you could do.

 

A BRS is minimally going to cost $12K. $12K buys a lot on an aircraft. That money could be used to make you powerplant system more reliable, better flight instruments, additional training; all of which may have a better payoff than BRS.

 

BRS has additional issues. Like Chrissi pointed out flying at night or over inhospitable terrain is where it shines. However, approach and departures are where a lot of the accidents happen. That means you have to make the decision to deploy very quickly and be reasonably sure that firing that beast off is the right thing to do.

 

Additionally, BRS is going to add weight, real estate, and CG issues, plus you will be the pioneeer. If the wife really wants BRS it may be a better idea to look at plane already equipped with one.

[Remi Khu]

There has been incidences where BRS can be a detriment. A few Cirrus drivers, overly confident of the BRS have pushed the safety envelope, only to perish while deploying the system at unsafe speed.

 

Personally, I'm not convinced that BRS is a panacea. The cost factor, IMHO, greatly surpasses safety. Once again, it boils down to common sense!

 

Just my $0.02...

[rsrguy3]

Hans,

 

Have you considdered the Spencer Air Car? You get foldable wings, a high thrust line and as a bonus you can land on a lake if you want or need to.

-Guy

[Hans S]

I think I've got her talked out of the BRS. I don't think either one of use realizes what a pain in the butt it would turn into.

 

 

As I was driving to work this evening, I work nights, I thought about another poss mod on a Cozy. If I understand this correctly, the canard stalls before the main wing. Because of this, you have to zip along a runway to faster than necessary to create the lift needed to raise the front end. My question is if the canard could have a hinge attached to the trailing edge. When you take off or land you could raise the leading edge up a few degrees to creates more lift and equal the main wing. Slower speed take off and landings could then be done which would mean you could use shorter runways. Does this make sense?

[CBarber]

Saw this at the Wings over Houston Airshow this weekend. They had a flying model (1/10 scale as well as a 1/4 scale) and a full size simulator using X-Plane with three projectors. It was fun.....Pretty darn ambitious though.

 

http://www.labicheaerospace.com/

[Jon Matcho]

It also is what my wife says is going to be there if our kids are going to be in it.

Consider that maybe your wife and kids don't need to fly much with you. Maybe this is about you wanting to build something, or just wanting your own personal aircraft to fly. I too originally had visions of taking the family cross country, vacationing, but have since come to realize that they won't be in the plane all that much, if at all for the first couple years (whenever that will be). In hindsight, I wonder whether I should have built a 2-place instead of a 4-place.

 

When you take off or land you could raise the leading edge up a few degrees to creates more lift and equal the main wing. Slower speed take off and landings could then be done which would mean you could use shorter runways. Does this make sense?

The Beech Starship had something like that engineered into it, supporting flaps as well. Search and download a copy of their patent for $2 at www.uspto.gov and get busy! In all seriousness, build ALL control surfaces to plans and fly before changing anything on your SECOND airplane.

 

It was fun.....Pretty darn ambitious though.

Finally, a flying car prototype that looks COOL! And a canard wing to boot.

 

So Hans, what do you expect is more your passion? Building or flying?

[Nathan Gifford]

...My question is if the canard could have a hinge attached to the trailing edge. When you take off or land you could raise the leading edge up a few degrees to creates more lift and equal the main wing. Slower speed take off and landings could then be done which would mean you could use shorter runways...

The advice about doing this on your second plane is sound advice. What you are trying to do is possible...HOWEVER...there is a considerable amount of work you would have to do plus investigate changes in roll authority at the slower takeoff and landing speeds you will be flying at. Additionally you will be adding weight to the aircraft and in places that will have a large impact on machine's CG.

 

To get up off the ground faster keep the aircraft on diet. Another option is a variable pitch propeller. The Cat's Meow (a Cozy MKIV) is flying with 200hp 360 with constant speed prop. Chrissi says it leaves the ground like a scalded cat.

[TMann]

My question is if the canard could have a hinge attached to the trailing edge. When you take off or land you could raise the leading edge up a few degrees to creates more lift and equal the main wing.

There were a couple of guys that tried that on their canards.

If it had not killed them, they could give us some feedback on the subject.

 

I believe the last comment they had on the subject was:

"Aw sh!t !"

[Marc Zeitlin]

There were a couple of guys that tried that on their canards.

If it had not killed them, they could give us some feedback on the subject.

Pointers to who, when, where?

 

While I believe that this is NOT a good idea, for many reasons, I've never heard that anyone tried it.

 

The reason for the takeoff roll/landing roll distance in canards is due to wing loading - very little of it is due to the canard configuration. This has been discussed on the mailing lists and fora many times previously. Look at any aircraft with similar wing/power loading - the takeoff/landing distances will be similar.

 

OWT's die hard.

[Jon Matcho]

The advice about doing this on your second plane is sound advice.

Whoops... that wasn't actually advice, but a stall tactic for Hans to get to that point and THEN ponder the magnitude of the question he asked in October 2007.

 

Another option is a variable pitch propeller.

Now we're talking... a much better approach to taking off on less runway!

 

OWT's die hard

"Old wives tale" for those of you who were as confused as I was with that TLA.