some newbee questions

[fmanh2]

Hi everybody!

 

I have recently begun the journey to learn more about how to build my own airplane. The canard type has struck me as being a quite good and efficient design on the whole. However, being the newbee I am, there is a lot to learn before undertaking this kind of project, and therefore I am forced to, ahem ask maybe dumb questions.

 

I am currently investigating airplanes that can be built from plans. The aircraft should carry upto 4 (2*90+2*75+25, all weights in kilograms, sorry, I am afterall european!) passengers with baggage, along with ample fuel levels for up 2.5 hours of flying. The only aircraft comming close seams to be the cozy mark IV. HOwever, even that design seams to be right there on the edge with those requirements. I was thinking of using the deltahawk 200 hp diesel engine (I kind of like the concept with a two stroke diesel!). My questions are:

 

1) Is there any experience of the deltahawk diesel engine in a cozy or similar design (besides the velocity)?

2) I am 1.90 meters (should be roughly, hahum, 5 ft 8" (?)), is the cozy cabin large enough when you are a bit longer than normal? I seem to recall to have seen that this is not an uncommon problem?

3) With a quick calculation it seems to be hard to meet the requiements above in regards of weight with the standar cozy (or am I simply missing out on something)? Is there any possibility to achieve a somewhat higher lift? I am aware of the balance of lift between the canard and the main wing. Or is there any alternatives aircrafts to look at?

 

I hope I haven't bothered you with my, perhaps stupid questions!

 

regards

JH

[Nathan Gifford]

...I am forced to, ahem ask maybe dumb questions...

No worries, mate. Most people have been there at one time or another.

...I am currently investigating airplanes that can be built from plans. The aircraft should carry upto 4 (2*90+2*75+25, all weights in kilograms, sorry, I am afterall european!) passengers with baggage, along with ample fuel levels for up 2.5 hours of flying. The only aircraft comming close seams to be the cozy mark IV. However, even that design seems to be right there on the edge with those requirements...

Yes you are just on the edge, but at least you are on the right side.

 

Doing a few quick conversions:

 

Cozy empty weight 477 Kg

Max front seat 181 Kg

Rear seat max 136 Kg

 

This leaves about 137 Kg for fuel. That is very close to the max fuel load (141 Kg).

...1) Is there any experience of the deltahawk diesel engine in a cozy or similar design (besides the velocity)?

I haven't heard of anyone flying the Deltahawk engine beside Velocity. It is still a pricey option.

 

One Cozy Classic (3 seater) builder is thinking about experimenting with deisels but he has just picked up his project and has not had the time yet to work on the engine.

 

One important thing to remember is that the powerplant and avionics will be among the last of your purchases. Depending on how much time you allocate to building your project, new engine solutions will likely be available by the time you are ready for them. At your stage, it is more important to make sure you want to build this project than to worry about a engine package.

 

...2) I am 1.90 meters (should be roughly, hahum, 5 ft 8" (?)), is the cozy cabin large enough when you are a bit longer than normal? I seem to recall to have seen that this is not an uncommon problem?

The Cozy is quite Cozy. As you note this is the general complaint. The first Cozy I sat in I found quite tight. However, when someone showed me what I was doing wrong, my opinion changed. Still most people are doing very small things to improve cockit space, but unless you are huge you should fit just fine.

...3) With a quick calculation it seems to be hard to meet the requiements above in regards of weight with the standard cozy (or am I simply missing out on something)? Is there any possibility to achieve a somewhat higher lift? I am aware of the balance of lift between the canard and the main wing. Or is there any alternatives aircrafts to look at?

I think you are at the maximums. Nat Puffer, the designer, has indicated that the plane is not intended to be flown at gross all the time.

 

On all canards the real concern is to stay within the CG range. While that's true for all aircraft, canards have particular problems when they exced their aft CG limit (remember its a limit, not a recommendation) and encounter a deep stall. Simply put you do not want to go into a deep stall.

 

There are certainly other planes to consider. Still the Cozy has a great useful load with very high cruise speeds. What is more is that there are many average, run-of-the-mill Cozys built by average builders, cruising around in the 170 knot range. That's quick in anybody's book, especially for one that can be built for $45,000 USD (you will have to convert to euros). Let's see someone else build a ship with these specs for that money.

[Jon Matcho]

Hi everybody!

Hello and welcome!

 

I am 1.90 meters (should be roughly, hahum, 5 ft 8" (?)), is the cozy cabin large enough when you are a bit longer than normal? I seem to recall to have seen that this is not an uncommon problem?

1.9 meters is 6' 3" tall, several inches taller than the designer. One common modification for the taller people is to move the seatback aft one inch or two (~2.5 - 5cm). Tall is not so much an issue as is being large.

 

I hope I haven't bothered you with my, perhaps stupid questions!

No question is stupid, only some answers and occasionally the people who answer them.

[fmanh2]

This leaves about 137 Kg for fuel. That is very close to the max fuel load (141 Kg).I haven't heard of anyone flying the Deltahawk engine beside Velocity. It is still a pricey option.

 

Yes it is somewhat pricey, I've noticed. The actual building of the aircraft is by it self the cheap part. The pricey part is the avionics and the engine. Being a aspiring (not yet though) IFR pilot i really would like to have the IFR equipment onboard. However, I fully agree with you on the fact that the cozy (so far at least) seems to provide most bang for the bucks. Being located in Sweden fuel costs will though be an important part of my calculations and even rather high purchase price could be offset by the lower consumption and fuel price induced by a kerosene/diesel burning engine. However, as you said, this is nothing I will decide in the first round.

 

Further more, as you stated, I have not even yet reached the conclusion that I should build an airplane, one step at a time. This is just some cautious preliminary question in an investigation which will take about a year to complete. On my agenda is also to find a pilot who has built this type of aircraft so I can talk to him/her about problems/flight characteristics and other things of interest. This is not a decision I take lightly.

 

One Cozy Classic (3 seater) builder is thinking about experimenting with deisels but he has just picked up his project and has not had the time yet to work on the engine.

 

What engine is he planning on using? I know about at least three diesel engines (among them the http://www.deltahawkengines.com/, http://www.thielert.com/en/aviation/engines.htm, http://www.wilksch.com/, and the zoche experiment), and I have visited dieselair.com and started to learn even more. Personally I am quite convinced that diesel engine is the way to go for several reasons, specially a two stroke variant. But as allways, it boils down to price in the end...

 

One important thing to remember is that the powerplant and avionics will be among the last of your purchases. Depending on how much time you allocate to building your project, new engine solutions will likely be available by the time you are ready for them. At your stage, it is more important to make sure you want to build this project than to worry about a engine package.

 

Point taken! And this is one of several steps...

 

The Cozy is quite Cozy. As you note this is the general complaint. The first Cozy I sat in I found quite tight. However, when someone showed me what I was doing wrong, my opinion changed. Still most people are doing very small things to improve cockit space, but unless you are huge you should fit just fine.

 

I am 6.3 ft tall, 90 kg, and well, relatively at least, fit (most of it is muscles...). I guess I have to find a small co pilot :-) My main problem is really that I am somewhat disproportionate, meaning, my legs are fairly long. I guess I have to test and sit in one of these constructions before I make up my mind ;-).

I think you are at the maximums. Nat Puffer, the designer, has indicated that the plane is not intended to be flown at gross all the time.

 

I do not intend to, but it is a feature when required ;-) What is, by the way, the Vne on this bird? I saw a reference to a jet powered machine elsewhere on this site, and I was kind of intrigued when the author said that 200 knots was the slowest he could achieve in level flight with without idling the engine... That is fairly fast... And I can imagine that the stress on the construction was considerable...

On all canards the real concern is to stay within the CG range. While that's true for all aircraft, canards have particular problems when they exced their aft CG limit (remember its a limit, not a recommendation) and encounter a deep stall. Simply put you do not want to go into a deep stall.

 

Hm. I can sort of imagine that given the flight characteristics of this machine... :-). How does this relate to the aboe given advice of moving back the front set an inch or so? Wouldn't this shift the Cg backwards and thus decrease the usefull load in the rear seats?

 

There are certainly other planes to consider. Still the Cozy has a great useful load with very high cruise speeds. What is more is that there are many average, run-of-the-mill Cozys built by average builders, cruising around in the 170 knot range. That's quick in anybody's book, especially for one that can be built for $45,000 USD (you will have to convert to euros). Let's see someone else build a ship with these specs for that money.

I am aware of this, and yes, economy is one of the more important parts here, I am operating on a relatively thin budget and whish to have a maximum of joy for the money. I have looked at the lancair and the glasair, and while being excellent airplanes, they are not really in the same league when it comes to the economy side (allthough, I dare say, they provide very good value for the money spent though).

 

I really apreciate all of your help!

 

regards

JH

[Nathan Gifford]

...What engine is he planning on using? I know about at least three diesel engines...

Try sending a message to Kumaros on this board. He's the builder who has looked at a number of engines and is planning to build a test rig on sailboat.

...What is, by the way, the Vne on this bird?. I saw a reference to a jet powered machine elsewhere on this site, and I was kind of intrigued when the author said that 200 knots was the slowest he could achieve in level flight with without idling the engine... That is fairly fast... And I can imagine that the stress on the construction was considerable...

I think its 220 knots, but I don't have the book right now. The jet Cozy was Greg Richter's (Blue Mountain Avionics) creation. If memory serves, he converted his rotary powered Cozy III to turbo jet.

...Hm. I can sort of imagine that given the flight characteristics of this machine... :-). How does this relate to the above given advice of moving back the front set an inch or so? Wouldn't this shift the Cg backwards and thus decrease the usefull load in the rear seats?

Actually the Cozy is far more forgiving to weight additions in the rear seat area. In fact, when flying solo it is very important to have the ballast weights in the nose. Failing to do that can lead to some very nasty surprises.

 

If you find it difficult to locate a Cozy, remember its the grandchild of the VariEZE. If you can locate either a Vari or LongEZE, they have very similar flight charateristics to the Cozy (the Cozy is mostly a widened LongEZE). The construction techniques are virtually identical. Also remember, the Cozy plans are cheaper!

[fmanh2]

Try sending a message to Kumaros on this board. He's the builder who has looked at a number of engines and is planning to build a test rig on sailboat.

 

Thanks!

If memory serves, he converted his rotary powered Cozy III to turbo jet.

 

Mazda RX7? It's the only commercial rotary (in the sense of Wankel) I know of... Other than the gnome engines from first world war ;-).

Actually the Cozy is far more forgiving to weight additions in the rear seat area. In fact, when flying solo it is very important to have the ballast weights in the nose. Failing to do that can lead to some very nasty surprises.

 

Hmm, I am not 100% sure I understood this? If it's forgiving for wight additions in the rear area, wouldn't the ballast go there? If I have understood it correctly (and note the 'If'), the whole point with the canard design is to let the *front* stall first (unlike an ordinary configuration where the tail actually stall the 'wrong' way and let the main wing fall through. When the canard stalls, it strives to lower the nose and thereby convert height to speed and regain a proper attitude. A to high weight in the front should then make the canard stall at a higher speed... But then maybe I have misunderstood the concept, I still have quite a few things to learn about this configuration, and I appreciate every oportunity to do so...

If you find it difficult to locate a Cozy, remember its the grandchild of the VariEZE. If you can locate either a Vari or LongEZE, they have very similar flight charateristics to the Cozy (the Cozy is mostly a widened LongEZE). The construction techniques are virtually identical. Also remember, the Cozy plans are cheaper!

I think I can locate an *EZE with some ease ;-). There is one within the club...

 

regards

JH

[Jon Matcho]

If you find it difficult to locate a Cozy, remember its the grandchild of the VariEZE. If you can locate either a Vari or LongEZE, they have very similar flight charateristics to the Cozy (the Cozy is mostly a widened LongEZE).

Good points Nathan, but I have been told that the VariEze is noticeably different in flight than the Long-EZ. Not much, but enough so that Long-EZs are valued a bit more.

 

The construction techniques are virtually identical.

The construction techniques are entirely identical.

 

Also remember, the Cozy plans are cheaper!

That's for sure!

 

I think I can locate an *EZE with some ease ;-). There is one within the club...

Lucky! What kind of 'club' is that?

[fmanh2]

The 'club' as was carelessly saying (I do not reall know If i am using the correct term here), is the place where I currently rent my aircrafts ad takes my lessons. Its located in Stockholm, sweden, botkyrka-barkaby flygklubb. I have visually identified and aircraft that I believe is an EZE, however, I will try to locate the owner and harass him with some questions...

 

regards

JH

[Jon Matcho]

I have visually identified and aircraft that I believe is an EZE...

Very cool -- I've never heard of having a canard in any club down here, although I suppose it's possible.

 

Consider yourself lucky if that's the case.

[fmanh2]

Very cool -- I've never heard of having a canard in any club down here, although I suppose it's possible.

 

Consider yourself lucky if that's the case.

Ordinarily 'down' is defined as 'south' (in sweden that is, this may not be the case in the anglosaxon tradition?). given the fact that I am located at N60, well, pretty much all of the US is located 'down' from my perspective. Apart from northern alaska that is ;-). Given the fact that I spend considerably time even further north, this should cover even most of alaska (About N66) ;-). Which, by the way, leads to the curious question about how efficient the heating system is in this contraption? I can assure you that 30 degrees (centigrade) below zero, is not to be taken lightly. Even more normal 15-20 degrees below can easily become lethal... Allthough I am not planning on doing much winter flying it could be worthwhile to investigate the provisions for such conditions.

 

Furthermore: According to the national EAA chapter we have 25 flying rutan constructions in sweden in total. Most of them located in the Stockholm area.

 

http://www.hobby.se/EAA/EAA-flygplan/SEXRS.jpg shows the one I have seen around in the local club. I think ;-). I will, I think, aproach him with some of myquestions ;-)

 

I thanks you all for you great help, you have really given me quite a bit of input and ideas.

 

regards

JH

[Jon Matcho]

Which, by the way, leads to the curious question about how efficient the heating system is in this contraption?

Considering that these planes have been designed by people who now live in some of the warmest areas of the USA, heating was not the highest priority. This issue does come up, and many have managed to get around it by tapping the massive heat source in the back. Other suggestions include warm clothes and electrically heated socks. I would think the issue would be actively addressed by anyone building in your area.

 

According to the national EAA chapter we have 25 flying rutan constructions in sweden in total. Most of them located in the Stockholm area.

Quite a presence if you ask me!

 

http://www.hobby.se/EAA/EAA-flygplan/SEXRS.jpg

Nice looking plane -- if you can get rides in it you're better off than most here. If you can fly it as part of a club, that's beyond anything I've heard of over hear. Good for you.

[fmanh2]

Considering that these planes have been designed by people who now live in some of the warmest areas of the USA, heating was not the highest priority. This issue does come up, and many have managed to get around it by tapping the massive heat source in the back. Other suggestions include warm clothes and electrically heated socks. I would think the issue would be actively addressed by anyone building in your area.

 

Quite a presence if you ask me!

 

Nice looking plane -- if you can get rides in it you're better off than most here. If you can fly it as part of a club, that's beyond anything I've heard of over hear. Good for you.

Thanks for your input! I am allways keen on learning more about this airplane. Currently my brother also seams to have caught the bug. Being a carpenter he is eying the IBIS construction which seama to be an efficient and simple to build design for one with all of the tools readily available. Not to mention the simple engine alternatives (rebuilt vw).

 

thanks again!

 

regards

JH