Cabin Width

I don't know if if is the place for this thread, but...

Has anyone heard of anyone else widening the cabin of the Cozy Mk IV. I think that even at 2 more inches, this could make a big difference in comfort and the ability to move around or have a knee board between occupants.

Don't yell at me if this is stupid, I know that others have raised the canopy an inch for more headroom but at least that does not change the canard and wing span. If the wider cabin increases the wing span, should the carard be widened as well?

I suppose that Nat may be the one to ask. I'm sure that he had different alternatives in mind while developing the 4 seater. I'm not trying to design this here and now, just asking if it had been done before.

Yes I'm sure 2 inches have been done. One builder in my area is widening his by 6 inches (at the front seatback, other bulkheads are less and the firewall is as plans, or very close to it).

Basically he built the tub to plans, got in it to make the vroom-vroom noises and didn't like the fit. So he cut it apart and added the extra width. Added a bunch of time to build, and I'm sure it will cause more headaches in the future, but he said that he just wouldn't be happy with the origianl width (btw, he isn't overweight). I'm not sure whether he changed any other dimensions (ie. canard length, etc).

Nat is totally against this as the tub provides some lift and changing its dimensions will also change the performance of the plane. The question is how much it will change it and whether the effect will be negative....

Anyway, I'm on the fence. I think I will make the changes suggested by Nat (ie. make the fron seat a bench), but also maybe add a couple of inches at the seatback only, that way reducing the changes to other parts.

One thing that everyone should keep in mind when trying out the Cozy for fit is that your mind can play tricks. I remember when I bought my Honda Civic that the first time I got in it I thought it was cramped (coming from a larger North American car). But soon (ie. 2-3 hours driving), I began to feel comfortable in it and now much prefer its "coziness" to the wide open nothingness I feel when I ride in somebody elses car. My point is that when you try out a Cozy it will feel small, but as long as you can move around a bit and nothing is jabbing you uncomfortably, you will probably get used to it and come to prefer it.

I did get in a tub last weekend. It's hard to tell exectly what it will end up like just sitting on fiberglass. What I need to do is really spend some time at the canards in Oshkosh. If I can talk some of the guys into letting me into a four seater to check the fit.

I know the cabin also provides lift which was one of my concerns. Six inches will actually make it wider than the Velocity (48 vs. 47.5) which is pretty roomy I think.

I saw a completed cozy in sport aviation. It was 1.5" wider. Of course I cant find it now.

Rutan has said that the strakes lift very little.

Are there any flying fat cozys?

In December I got the opportunity to visit Falcon Field and spoke with Mr. Puffer in person. I also used the opportunity to sit in his aircraft and "try it on for size." While I'll admit there was not a lot of extra room, I didn't feel at all cramped or squeezed in. There was clearance for my head, twisting rapidly from side to side put me nowhere near the canpoy, and everything was within arms reach. The only two complaints I had were that the rudder pedals were located in my shins and I couldn't reach the stick unless I jammed my elbow back towards the strake. Width was not an issue, and I have a fairly large frame.

After discussing my fit with Nat we both agreed that no modifications were absilutely necessary, other than to move the rudder pedals and maybe move the seat backwards a little, to give me a better angle on the stick. Even that was not really necessary because it'd be simpler to change the angle on the stick. While I liked the thought of the higher canopy, it was not at all necessary. I'll wait as long as I can to make that decision.

I tend to agree with Rui's comment that you'll get used to the dimensions after you've spent some time in the aircraft. It could be that I'm one of the uncommon ones, but I felt used to it the first time I got in. My wife and I were both struck with how well it fit. My car is nowhere near that comfortable.

True, I may be making more out of this than I need to. I haven't even st in a completed one yet. It's just the engineer coming out in me.

Check out this Cozy at Eric Cobb's website. It's a wide body.

http://www.ecobb.net/for_sale2.htm

For anyone interested, I am building a Cozy that is 8" wider than plans from F22 to the front seatback and 1" taller. It then tapers to 4" wider at the firewall. I did this to, hopefully, keep suffiencent airflow to the prop.

I'm just finishing chapter 6. It has taken me about twice as long to build with these mods. I have beefed up the structure quite a bit also.

I'll try to post pictures on a web site soon.

Steve

Some other guy was building an enlarged version of the Cozy MKIV a while back. He termed it the "King Cozy" to be powered by an 540. Don't know what happened to him or his project.

http://www.geocities.com/CapeCanaveral/Hangar/1165/index.html

Yea not much since 1998. Maybe he never finished and his wife did kill him:D

Looking at it, our Cozy might be slightly wider than the King Cozy. I figure what I loose from the 10% increase in frontal area should be made up with the retracts. Also, I'm using a 300HP Turbo Mazda that will be capable of 200Hp continuous.

I hope to get 225 knots true at 10,000' plus. If it's a hog, I'll install a Mazda Turbo'ed 3 rotor capable of 400hp.

Anyway, there are a lot of mods to do if you're gonna widen a Cozy. I'll only know the aerodynamic effects on some fatefull date in the future. I have used X-plane, Airplane PDQ, and now MS Flight Sim to evaluate the new layout. I even thought of increasing wing area a bit, but decided against it as too many changes to the pie make dog food.

Originally posted by TES111

http://www.geocities.com/CapeCanaveral/Hangar/1165/index.html

 

Yea not much since 1998. Maybe he never finished and his wife did kill him:D

I think he got a job somewhere else or something and sold the project.

SL

I talked to JD at Infinity Aerospace over the weekend. He said that the Roberts' King Kozy was sold after the company he worked for shut down. Apparently he took over some customer requests and didn't have the time to work on it and simply bought a production plane.

I've tried to track it down... the last I heard it was somewhere in Alabama. I for one would definately like to see it if anyone has more information.

I'm thinking of going 6" wider all the way back. I think some of the prop blockage will be averted by using a rotary which does not require the bulge in the rear fairings. My first concern was my weight and height. I actually fit fine from the shoulders down. Everything was comfortable. But at 6'0" with wide shoulders, I couldn't sit with my shoulders back or get a good angle on the control stick.

I don't think adding 3" on each side will change the dynamics in an extreme fashion. But I do plan on watching weight and balance closely and taking extra precautions during flight testing.

Nat made the Long-EZ wider creating the Cozy IV... I think others continuing the process in small increments is just a natural progression of the design.

I thought I was too wide in the middle... turns out I'm too wide up top.

MT,

Why go 3 inches each side? You don't look like you really need that much. Every inch counts for a lot, as they say.

It looks like the longeron is touching you're shoulder, so why not add an inch there, maybe an inch & half tops, then taper it back to the plans firewall? This would save you a lot of "rattle down" changes.

While you're at it, carve out the inside of the armrest to let the torque tube just miss the outside skin, and you'll get an extra inch or so there too. Add the electric speed brake and dispense with much of the center console. Keep the heat duct for structure. Its below the seats anyway.

I saw MT's picture in Nat's plane. Unless he is profoundly pear-shaped (not visible below the longerons) I'd guess he'd be OK with a couple of inches wider. I'm 6'3", 250#. long torso. I sat in Slade's airplane and was only mildly uncomfortable; most of that was through the shoulders and my head too close to the canopy. I intend to add 2" to the width of the airplane stem to stern and "steal" two more internally using the console modifications John has already outlined. Adding the width at the front seat and tapering to the nose and firewall would involve redesigning the fuselage side jigs for a different taper than the design has and would result in scads of other "unintended consequences". A straight increase in width would involve adding 2" to EVERY bulkhead, the main spar and canard. That's about it. I worried a great deal that the extra width would amount to unacceptable additional masking of the prop, but John pointed out that since I will have no cowl cheeks, the worst I could do with 2" wider tub was break even with the prop masking from Lycosaurus cowl cheeks. I also aim to lengthen the nose ala' long-nosed EZs.

Aside from widening the tub, 3" - 4" inches of shoulder (and head) room can be gained by widening the canopy from the design shape so that it goes pretty much straight up from the fuselage side and doesn't start curving inboard until it is several inches above the rails. That changes the current canopy, which was intended to be strictly a from the neck up instalation to one that can accomodate shoulders. This will also marginally increase the flat plate drag, but not nearly as much as what I will gain with retractable main mounts. I would expect my cruise drag to be the same as or perhaps just a tad less than that of a box-stock plane, but I will be getting MUCH more power at altitude from a turbo normalized 13B. Expect to cruise at around 15k' - 18k' at something in the vicinity of 250-300 kts.

Now all I need to do is subdue mouth running and focus on building .... Jim S.

I sat in Nat's airplane last year at OSH. The problems I encountered were headroom with the canopy closed and legroom below the instrument panel. It was just generally tight. So we decided to go for the King Cozy concept. Whatever we loose by the 10% increase in frontal area should be made up by the Infinity retracts and more power (50% more). If I don't get 200 KTAS were going to rip out the Mazda 13B and put in a turbo'd 20B.

John's statement about ripple down changes is understated. I am taking about twice as long as most to complete, sometimes I get to do things twice! I am documenting the changes in case anyone in the future is interested.

This thing is like an ugly child. Sometimes I think it's hideous, other times beautiful.

where can we read about these changes?

I'll recreate my web site over the next few months. I will post pictures and changes there. e-mail me at steve@bigdaddie.net to get my phone # if you'd like to talk about the changes.

Again, there's A LOT to consider when making this thing bigger. I thought of 1,000 of them and missed 1,000,000 I'm sure. Time will tell.

Dear All

Its not called to Cozy for nothing, if it was wider it would be called the Comfortable.

Pick one:

• Fast and Cozy
• Slow and Comfy

A related discussion on this topic continues in this thread.