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The new Tornado sport jet

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Old 11-09-2011, 08:34 AM
  #1676
megafly
 
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Default RE: The new Tornado sport jet

I dont't calculeted my cg by weight, my nose landing gear is way heavier than modelldeu told me to put.
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Old 11-09-2011, 08:43 AM
  #1677
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Default RE: The new Tornado sport jet

i also agree i was a little worried about just doing the cg by weight in all my years of building and flying ive never done it that way either, but after talking with henry this meathod was easier so why not try something different. my tornado came in a 16.4 pds but when i was in the air my plane wanted to keep doing a nose dive and i hade no more trim left i will see if the balnce is off by using a balancing scale and see where she comes up.
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Old 11-09-2011, 09:49 AM
  #1678
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Default RE: The new Tornado sport jet

Balancing via weight on the nose will only be accurate if everything is identical on Henry's plane and yours (ALL landing gear geometry: strut angles, length, wheel size, crookedness of the blocks the gear is bolted to, etc...). If anything is different, you must compensate for it.

Now close is likely good enough, but measuring the actual CG location is always best!!!
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Old 11-09-2011, 09:57 AM
  #1679
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Default RE: The new Tornado sport jet

My first flights it was balanced using the thumbs on balance point metod, and on constant bank turns the plane wanted to keep on rolling but after many flights I decided to do the nose gear weight balance and I must say it was a total different plane afterwards it just flies so much better after the rebalance. There is 4 tornados flying around here and all had been rebalance with a scale and all pilots agree it that flies so much better when you put 1.5 lbs on the nose. When I did mines it had 1.8 lbs on the nose and my bats where in front of the main tank, to achieve tha 1.5 lbs I had to put both batteries( 2600 Li-ion and 5200 Li-ion) all the way back in the fuse under the turbine.

Hope this helps.
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Old 11-09-2011, 10:00 AM
  #1680
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Default RE: The new Tornado sport jet

The point being that it flies best when the CG is properly positioned. How you do that is up to you. But if you want to be certain and cut out most uncertainty, measure where the CG is and make sure it is right!!!
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Old 11-09-2011, 10:06 AM
  #1681
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Default RE: The new Tornado sport jet

Cg location in the manual "CG Location- 12 3/4 inch back from the leading edge measured at the wing root," is wrong! If you balance that way the plane is going to be very nose heavy.
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Old 11-09-2011, 10:09 AM
  #1682
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Default RE: The new Tornado sport jet

Does not change what I wrote! Note I said to be sure the CG is properly positioned. I did NOT say "put it in the wrong spot". If the CG in the manual is incorrect, use the correct CG!!!!
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Old 11-09-2011, 10:17 AM
  #1683
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Default RE: The new Tornado sport jet


Quote:
ORIGINAL: megafly

Cg location in the manual ''CG Location- 12 3/4 inch back from the leading edge measured at the wing root,'' is wrong! If you balance that way the plane is going to be very nose heavy.
Megafly I wouldn't say its wrong, its just conservative, the Tornado is intended to bring new jet flyers so you don't want a new pilot with a Tail heavy Jet once you get used to the jet then bring the CG back to your likings.
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Old 11-09-2011, 10:22 AM
  #1684
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Default RE: The new Tornado sport jet

But with that cg the plane can't slow down for lanndings, it not conservative it's nose heavy, and the 1.5 lbs on the nose, at least for me the plane was tail heavy...
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Old 11-09-2011, 12:33 PM
  #1685
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Default RE: The new Tornado sport jet

I'm shocked that my Tornado even flies................ dry weight is 14 lbs 3.2oz, blocked her up level and weighted the nose wheel........... 1lb 2oz, i guess i need to add 6oz of lead before the next flight
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Old 11-09-2011, 02:58 PM
  #1686
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Default RE: The new Tornado sport jet


Quote:
ORIGINAL: megafly

Cg location in the manual ''CG Location- 12 3/4 inch back from the leading edge measured at the wing root,'' is wrong! If you balance that way the plane is going to be very nose heavy.
13" works very well for my Falcon, so it can't be very nose heavy if balanced at 12 3/4", that 1/4" difference won't make too much difference. I have no problem at all slowing down or loosing elevator authority at low speeds so I'm definately not nose heavy.
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Old 11-09-2011, 03:19 PM
  #1687
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Default RE: The new Tornado sport jet


Quote:
ORIGINAL: KC36330

I'm shocked that my Tornado even flies................ dry weight is 14 lbs 3.2oz, blocked her up level and weighted the nose wheel........... 1lb 2oz, i guess i need to add 6oz of lead before the next flight
Your nose wheel would actually weigh a bit more, since yours is dry and Henry says to balance with the UAT full. But your point is well taken. The 1.5 on the nose wheel only works if the total weight is the same. BTW where is the CG located on the wing? Do you agree with the 12 3/4 figure?
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Old 11-09-2011, 03:29 PM
  #1688
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Default RE: The new Tornado sport jet

UAT full is dry weight............, you always balance with UAT full, it's considered part of the dry configuration.

my CG is a good bit back from the recommended, i put it there (as suggested in the instructions), flew it and adjusted till it was where i liked it, and i didn't recheck and measure it.
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Old 11-09-2011, 03:47 PM
  #1689
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Default RE: The new Tornado sport jet


Quote:
ORIGINAL: DrYankum

..... BTW where is the CG located on the wing? Do you agree with the 12 3/4 figure?


Mine is at 13".
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Old 11-09-2011, 03:53 PM
  #1690
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Default RE: The new Tornado sport jet

just measured, i'm a tad over 13 5/8", it flew fine at the recommended 12 3/4 but it wasn't how i liked it. with more power (i've got a P-60SE on mine) the more forward CG wouldn't of been as much of an issue to me.
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Old 11-09-2011, 07:34 PM
  #1691
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Default RE: The new Tornado sport jet

Our Tornado came out at !7lbs dry with the UAT full. We balanced it at the 12.75" dim. listed in the manual. We double checked the nose gear weight and it was 1.8lbs. Had we used the 1.5 lbs, we would have been tail heavy. The 1.5 lbs will only be accurate if you have the same emty weight as the Modelbau listed emty weight. At 12.75" the balance is perfect on our Tornado.
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Old 11-10-2011, 03:42 AM
  #1692
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Default RE: The new Tornado sport jet

Does not matter what the overal weight is, if you get 1.5Lbs on the nose wheel the C of G will be in the same place no matter the overal weight, think about it, put 6lbs of lead in the back, to achive 1.5lbs on the nose wheel you will need approx 12lbs of lead in the front to counterballance the load, (assuming a 2:1 ratio of distance to the C of G) you have just increased the weight of by 18lbs but still only have 1.5lbs on the nose wheel, unless it has given way under the weight.

The thing that confuses the issue is that the fulcrum (main UC) is not on the C of G, but if we think of the fus as a simple beam it starts to get a little clearer.

Mike
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Old 11-10-2011, 03:50 AM
  #1693
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Default RE: The new Tornado sport jet

Mike,

Assume that you have a 10lb model and then you place a 10lb weight exactly on the c.g. Are you saying that the weight on the noseleg scales won't change?
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Old 11-10-2011, 03:59 AM
  #1694
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Default RE: The new Tornado sport jet

No, its the problem as I tried to explain above, because the C of G is forward of the fulcrum the weight on the nose wheel will go up by the multiple of the distance, its only if you distribute the load at either end of the beam that the reaction at any point will stay constant, in our scenario the weight increase is likely to be because of a heavier turbine that has to be compensated for by moving the batteries/UAT etc.

Put this another way, put that 10lb weight over the main wheels/fulcrum?

Mike
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Old 11-10-2011, 04:13 AM
  #1695
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Default RE: The new Tornado sport jet

If you increase the weight of a plane, and keep the CG at the same exact point, I guarantee you that the weight on each wheel MUST go up (unless, of course, you move it to a low gravity world)!!!!
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Old 11-10-2011, 04:32 AM
  #1696
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Default RE: The new Tornado sport jet

Yes the weight on each wheel will go up, but if the load is universally distributed the weight of the beam/fus is irrelevant, the C of G is so close to the main wheels on most airframes that the difference to the weight on the nose wheel is disproportionally small to the overal weight increase and that is the problem, because the C of G is in front by a small margin from the fulcrum (main wheels) the weight on the nose wheel will go up by a small amount, if the C of G was on the main wheels the difference in overal weight would not alter the weight on the nose wheel as long as the weight was a UDL (universally distributed load).

All I was trying to do was explain that the overal weight of the airframe does not make a great deal of difference to the position of the C of G taking into account the weights that we put in our airframes and how we distribute it, they would largely be within the C of G range of the airframe.

Mike
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Old 11-10-2011, 04:44 AM
  #1697
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Default RE: The new Tornado sport jet

But the point is: If you increase the weight of a plane, and keep the CG at the same exact point, I guarantee you that the weight on each wheel MUST go up (unless, of course, you move it to a low gravity world)!!!!
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Old 11-10-2011, 04:51 AM
  #1698
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Default RE: The new Tornado sport jet

Mike, you don't own a blue cap by any chance ?

[youtube]http://www.youtube.com/watch?v=txp19ZNtFn8&feature=related[/youtube]
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Old 11-10-2011, 04:54 AM
  #1699
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Default RE: The new Tornado sport jet

Blue, Green and Brown. LOL

Mike
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Old 11-10-2011, 04:57 AM
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Default RE: The new Tornado sport jet

BaldEagel: You have given me a lot of good info in the past... (including mounting my engine at 0 degrees thrust) but in this case, you're incorrect.


As the weight changes... the scales have to change. Yes, the CG is in front of the rear tires, so the weights at the tires will change as a ratio of the distance from the CG. Weighing a single leg will not give you a valid CG.

Also... for the guys who said it has the be the same weight as the Modellbau demo model are not right either. It has to be the same in every respect. Think about this... what if I used full sized, metal gear servos out in the tail, but then I used small lipo batteries, and they are, and I had the exact same overall weight. By logic, I have a lot more weight at the tail than they do. SO... to use the 1.5Lb reliably... you have to not only use ALL the same equipment they used... but it has to be located in the same place.

A second example would be if I used a straight rear landing gear leg, or a trailing link. Lets assume they are the same weight. But the rear tire will shift back 1/4" or more from the straight leg. Now... a tire moving back a little will not affect the CG much, (in reality, it will move the true CG back) BUT, the effect on the scale is that the front tire will become heavier.


Anyway... what I'm saying is, the responsible thing for Modellbau to do is to NOT give a nose wheel weight. By it self... it's a dangerous number.



****** EDIT ******

Here's an FAA wights and balance PDF


http://www.faa.gov/library/manuals/a...83-30_Ch04.pdf
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