Jump to content
matter

Cozy Girls Strake Mod and Front Seat Weight Limit

Recommended Posts

If the AeroCanard is built using the premolded parts, is it still possible to incorporate the strake mod? Also whats the weight limit for people in the front seat in both the Aerocanard and the Long-EZ. I weigh in at just under 240 so Im curious. Thanks

Share this post


Link to post
Share on other sites

If the AeroCanard is built using the premolded parts, is it still possible to incorporate the strake mod?

Yes, no harder (or easier) than if doing this modification on a Cozy Mark IV.

 

Also whats the weight limit for people in the front seat in both the Aerocanard and the Long-EZ.

The AeroCanard is based on the Cozy Mark IV, which has a front seat limit of 425 lbs. The AeroCanard flight testing manual actually doesn't come out and say what the limit is (as far as I can tell after a few minutes of looking), but does give you a procedure for coming up with the figure yourself as part of flight testing.

 

The Long-EZ "can handle pilots or passengers up to 250 lbs."

Share this post


Link to post
Share on other sites

I've read at least one builder's description of increasing the length of the canard by a couple inches to raise the front seat weight limit. I know this is right in the middle "oh, you crazy girl, why you wanna be a test pilot?" country, but I'm wondering if anyone has put together a chart of what kind of canard mods can give what kind of max front seat weights without "defeating" the canards role in stall resistance?

Share this post


Link to post
Share on other sites

...I'm wondering if anyone has put together a chart of what kind of canard mods can give what kind of max front seat weights without "defeating" the canards role in stall resistance?

Sorry to be so short, but "no" aside from Nat Puffer when he first went through the initial flight testing where he decided to shorten canard length by 3" on each side.

 

You can do the same -- build a per plans canard and test that. If you need more than 400 lbs in the front seat, you can build a wider canard and test with that.

Share this post


Link to post
Share on other sites

The AeroCanard is based on the Cozy Mark IV, which has a front seat limit of 425 lbs. The AeroCanard flight testing manual actually doesn't come out and say what the limit is (as far as I can tell after a few minutes of looking), but does give you a procedure for coming up with the figure yourself as part of flight testing.

 

The Long-EZ "can handle pilots or passengers up to 250 lbs."

The weight carrying capability and it's location is not a product of the construction strength of the aircraft,(all right-- for you purests useful load is) but is solely a product of appropriate W&B. Keep yourselves safe and learn how to do these calculations, especially in an EZ type craft.

 

When done with your plane (and before this stage to determine where to place your battery and other heavy objects) do a weighing W&B. This will tell you all you need to know in terms of what and where and how much you can place it in the aircraft (and if you have to loose weight) (subject, of course to flight testing approaching these limits). Remember the W&B stats given in the manual are for one aircraft only, the prototype. These figures may or may not be accurate for yours(although they may be close). Your specific configuration may or may not need ballast. You may or may not be restricted to the stated front seat loading. There are a lot of may or may-nots but they can all be answered by clculation.

 

The next time someone says to you, "Wait a moment," A anardian should hear, "WEIGHT AND MOMENT"

 

Just thought I'd give a balanced view

Share this post


Link to post
Share on other sites

Keep yourselves safe and learn how to do these calculations, especially in an EZ type craft.

Absolutely! If the W&B calculations puts the CG within the acceptable range you will be fine (assuming the ~400 lb passenger does not stand on his big toe in that one weak spot in the middle of flight).

 

That raises an interesting question though -- what is the theoretical maximum in the front seat with no balast, nothing in the rear seat, and full tanks? I'll try to figure this out later...

 

Just thought I'd give a balanced view

And with 2 related puns! Will that wit of yours ever run dry? :)

Share this post


Link to post
Share on other sites

.... If you need more than 400 lbs in the front seat, you can build a wider canard and test with that.

My W&B allows me up to 450 lb. in the front seat with no ballast to get to the forward CG limit. Nat's 400 lb limit is artificial - he was not able to support it in a discussion last year on the mailing list, if you remember. He was using it as a "safety factor" on forward CG limits, but there already IS a forward CG limit, and I've tested my plane at it at all weight ranges.

Share this post


Link to post
Share on other sites

Nat's 400 lb limit is artificial - he was not able to support it in a discussion last year on the mailing list, if you remember.

Yes -- that one was hard to forget.

 

The Cozy Mark IV Owners Manual says:

  • Weights, p3, 2nd para. "The Co-Z plans model Mark IV, with an O-360A Lyc. engine, light-weight starter, alternator, and throttle body, and with the canard shortened in span to 145" leading edge tip-to-tip has a 250 lbs. minimum and 425 lbs. maximum front seat limit.
  • Weights, p3, 3rd para. "The back seat can structurally accomodate a maximum weight of 300 lbs, if the gross weight of 2,050 lbs. allows.
  • Cockpit, p5, 1st para. "Although the front seat will physically accommodate a pilot or passenger 6 ft. 4 in. tall weighing more than 200 lbs. in comfort, the combined weight of pilot and passenger in the front seat should not exceed 400 lbs. The rear seat can accomodate a combined passenger and luggage weight of 300 lbs.
  • (Newsletter #44) Aft C.G. Flight Tests, 15th para. "When the c.g. range was moved farther aft by shortening the canard span, we needed to make sure that we weren't sacrificing maximum front seat weight limit. To evaluate this part of the flight envelope, we went to altitude, moved the c.g. to 96.7, established a rate of descent of 500 fpm and 80 knots, and made sure we had plenty of elevator power to flare. Then we made a couple of landings and takeoffs at this c.g. This c.g. calculates to a front seat weight of 460 lbs. in our plans model, which is well over the maxunum we have been quoting."
Having read newsletter 44 I can see where all the commotion comes from. What I don't understand is where 300 lbs. in the rear comes from. Not considering structural limitations, why would that limit need to exist if the rear is directly in the C.G. range?

Share this post


Link to post
Share on other sites

 

And with 2 related puns! Will that wit of yours ever run dry? :)

Actually, John, I had four, but my wit was only operating at 1/2 speed :bad:

Share this post


Link to post
Share on other sites

IIRC the front seat weight limit for the Aerocanard was said to be 475lbs per Al Aldrich.

Share this post


Link to post
Share on other sites

As far as I know, there's never been an actual structural test on the seat weight limits in these planes.  Limits of 400, 450, 475, 500 pounds, etc. are all arbitrary and without any testing.

 

Also, with regard to the AeroCanard, understand that there are plans-built models which are no different whatsoever than a Cozy Mark IV structure in terms of layup schedules.  I would discount any consideration for the AeroCanard in a discussion of front seat weight limits.

 

Here are two other "lively" topics on front seat weight limits:

 

http://www.canardzone.com/forum/topic/18413-front-seat-wieght-limit-for-cozy

 

http://www.canardzone.com/forum/topic/16640-modifying-the-sides-for-more-width

Share this post


Link to post
Share on other sites

I have flown my former Cozy iii way forward of the placard CG. A 240 lb. pilot would not make much difference in an EZ and the C-IV is more tolerate of extra crew weight. Weight forward does increase the rotation speed and, for an off-airport landing, the amount of energy you'd have to dissipate due to higher glide speed.

 

It is more of a factor in the C-III. Nat and Shirley were small people. It was a good airplane for them; a bit undersized for today's Americans. I have always thought a C-III in tandem would be a pretty good configuration. Lots of room in front for gear and snacks. :-)

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...