Potential New Owner -- unfamiliar

[Roger Lee]

Hi Larry,

 

You will not have a physical issue with extra weight.

[Doug G.]

I use your W&B spreadsheet all the time Adam. (Modified to my plane of course,) Thanks.

Also this explains why I once saw an SW with two 20 lb. dumbells in the baggage compartment.

[Tom Baker]

PUtting 25 lbs in the luggage on EITHER side will work just dandy. Fuel is never totally balanced either. You guys are too much. My wife is NOT going to wear a divers belt to fly a plane. Laughing. She puts a duffle bag full of dead body parts in the right seat and puts the seat belt around it. Satisfied?

 

If you look at the AOI it calls for a minimum crew weight of 120LBS. You can put 25 lbs in the bagage if you want, but you would still need to add 30 lbs of ballast in the crew area. 30 lbs of dead body parts would work OK I guess. I just hope she doesn't decide to take you for a ride.

[FastEddieB]

PUtting 25 lbs in the luggage on EITHER side will work just dandy. Fuel is never totally balanced either. You guys are too much. My wife is NOT going to wear a divers belt to fly a plane. Laughing. She puts a duffle bag full of dead body parts in the right seat and puts the seat belt around it. Satisfied?

 

If asked, how many "souls on board" would that be?

[Ed Cesnalis]

...The baggage area is inside the envelope...

 

 

Huh? The CG envelope is about 5" from the fore to aft limit at 1,000lbs. At 1,320 lbs it is less than 4".

 

When you say the baggage area is inside the envelope you demonstrate that you don't know what the CG envelope is. The baggage area cannot be inside something that is 5" long.

 

The 120lb limitation suggests that the aft envelope limit would be at issue but If I run some calcs it seems like the foreward limit can be exceeded even with a 90lb solo pilot. It is hard to see the reason for this limitation when you look at a W&B.

[Runtoeat]

Originally my W&B spreadsheet didn't account for baggage. I realized that this could be a critical factor so the spreadsheet I've posted on the previous page now allows one to include baggage weight into the W&B calculation. I assigned an arm of 81" for the calculation which is about mid-point in the cargo bay. Adam, my W&B spreadsheet is just a small example of what lies burried in this forum. I sometimes go back thru postings to see what I may have missed over the last few years. Eventhough I've been here, there are things I've missed - or more likely forgotten :wacko:

[Ed Cesnalis]

The baggage compartments are inside the envelope. They have a 55lb limit each side. if you could not calculate the baggabe weight then your W/B is not going to come out right and you will have trouble elevating the tail if you overload it.

 

The envelope is about 5" long. The baggage compartment cannot be within the envelope.

 

The envelope is a percentage of the MAC ( mean aerodynamic chord ) something 25% to 50% of the MAC and this envelope does not include the luggage.

 

We are not trying to locate weight within the envelope. Weight is located from prop to tail. We are arranging the weight so that the CENTER OF GRAVITY is within a 5" envelope.

 

If you add ballast that was intended for the cockpit to the baggage area the result is a shift of the CG to a more aft location.

 

If you use the above thinking to overload the baggage you can result in an aft of envelope CG and pitch sensitivity that is beyond design.

 

CG too far aft results in unwanted sensitivity all the way to uncontrollable in pitch. CG too far forward results in heavy stick forces all the way to inadequate stab deflection.

 

gbiggs you are wrong on both accounts, baggage is not in the envelope and overloading it results in a tail that would be too easy to raise ( and lower )

[bseager]

What is everyones best guess on what the CT is actually capable of from a gross weight perspective? I expect 1500 pounds would not be an issue.

[FastEddieB]

What is everyones best guess on what the CT is actually capable of from a gross weight perspective? I expect 1500 pounds would not be an issue.

 

I'm glad you "expect" that.

 

And that you're curious about other's "guesses".

 

Maybe once we gather all the guesses and expectations we could consolidate them and then CT pilots could print them out and carry them in the plane to show the FAA (or Canadian equivalent) in the event of an over gross "issue".

 

Anyway, my best guess is that at 1,321 lbs. you're in uncharted territory.

 

Next?

[Ed Cesnalis]

At what gross weight did the 2 Indian CTs that flew around the world fly at?

 

Eddie,

 

People do pilot aircraft over gross for legitimate reasons, like to ferry across an ocean. Many of us have seen people operate at well over 1,320lbs so I at least have seen it with my own eyes. I would rather be informed than to call the subject off limits.

[bseager]

Exactly Charlie Tango, in Canada the number is actually 1232 pounds so it is clear the regulatory limits don't actually take into account the individual capabilities of the different aircraft.

[FastEddieB]

I'll stipulate that one can fly a CT above 1,320 lbs and probably not come to grief.

 

I'll also stipulate that ferry permits can be issued to operate well above gross weight, on a limited basis and with certain restrictions. I have no idea about the Indian CT's - I'm not familiar with the rules they were operating under or possible waivers.

 

But I'll still invoke the slippery slope: Once we've moved 1,500 lbs into our comfort range, does anyone really think that 1,501 will cause problems? Or 1,550? Or 1,600? Or more?

 

And I'll continue to use "The Most Conservative Action" as my guiding principle. In this case, I think its to operate within legal limits. What others may do is their own concern, and I wish them well.

[bseager]

I didn't intend to advocate for violations of applicable regulations. I was curious since the Light Sport Regulations and the Canadian Advanced Ultralight Regulations somewhat arbitrarily assigned MTOW. 1320 for the US (1400 on floats?) and 1232 for Canada. As a result I don't think the actual design MTOW for the CT figured into the thinking in either country. I was curious if anyone knows what the actual design MTOW for the CT series is?

[FastEddieB]

bseager,

 

I like the way you phrased that a lot better!

[FastEddieB]

BTW, I'm not immune to this sort of theorizing.

 

Here's a Sky Arrow 650, certified to 1,433 lbs, that looks almost exactly like mine (a 600 Light Sport).

 

 

 

(click to enlarge)

 

Still, I cannot be sure if any structure was lightened to reduce the empty weight when they came out with the Light Sport model, and I stick to the 1,320 lbs just to be safe (and legal).

[chanik]

http://echoflightusa.com/CTLE.html

Well, apparently it is at least 1500lbs since the 'police interceptor' version is approved up to this. I fly at max gross quite a bit and the CT still leaps off the ground. Plus better glide ratio and maneuvering speed. All upside.

[FastEddieB]

 

Well, apparently it is at least 1500lbs since the 'police interceptor' version is approved up to this.

 

Are you certain there are no other changes to that version?

[chanik]

I am reasonable sure FD didn't structurally redesign the CTLS for the small handful of CTLEs they might make. If you stay in CG bounds, then the net effect of an extra 180lbs is a 6.6% increase in stall speed

[WmInce]

. . . "I expect 1500 pounds would not be an issue." . . .

 

Adding 10 knots to the stall speed isn't an issue?

 

Performance numbers are only valid if the airplane is operated within the manufacturers specified flight envelope.

 

At 1500 lbs., say goodbye to light sport as a category.

 

At a gross weight of 1500 lbs., just what are the stall speeds at the different flap configurations?

[chanik]

They would all be 6.6% higher so just 2 - 2 1/2kts. FD must have approved the increase but 1500lbs puts it in Public Use, so not legal for LSA.

[FastEddieB]

My wife did her solo pattern check today WITHOUT ballast to get to the minimum 125lbs in the cockpit. She weighs just 90 lbs. She said the CTLS handled perfectly but noticed just after takeoff the plane ascended noticeably faster. So that settles the minimum cockpit weight problem finally.

 

Really?

 

Did she have a chance to check out every corner of the plane's envelope? Spin recovery? Oscillatory or harmonic issues with the gear when too lightly loaded? And so on.

 

I guess you're being serious here. If you are, your wife has chosen to second-guess CT's engineers, and assume that they stuck in a limitation for no valid reason, one that she feels free to violate based on that assumption.

 

Please be very careful with this attitude. She got away with it this time - there may come a time when she discovers WHY the engineers inserted that limitation, and I hope that discovery does not come with a cost. And I'd further want to seriously consider before posting about illegal flight operations.

[sandpiper]

Only one Indian CT flew around the world. There were 2 pilots in it except for, I think, one leg where they needed extra gas. I don't know what gross weight they flew at.

 

There were 2 Swiss CT's that flew around the world at a later date. One pilot each because there were aux tanks where the right seat was. FD, I heard, gave them one time trip approval for 1600#, or slightly more, gross.

[FastEddieB]

I apologize.

 

Good luck to both you and your wife in your flying pursuits going forward.

[FastEddieB]

Understood.

 

If the flight school is saying, "You know that Limitation in the POH about minimum crew weight? Don't worry about it. Just go fly!"...

 

...then the problem I see is not that the plane won't probably* fly just fine with less than the minimum crew weight specified. It probably will.

 

It's the message it sends to a student that it's OK to pick and choose which Limitations they choose to follow.

 

I'd personally want something in writing that CT authorizes flight with less than the POH minimum crew weight.

 

In the event of a mishap, even one totally unrelated to weight distribution, the FAA really does sometimes show up with scales, and remember it's the pilot-in-command who's ultimately responsible for proper loading and adherence to Limitations.

 

Anyway, bygones!

 

 

*whenever I see the word "probably" used in a context like this, it sets off alarms.

[Doug G.]

As far as the 1500 lbs. suggested earlier - flying at that weight automatically takes your plane out of the Light Sport category and it loses its airworthiness certificate. If it is enforced you have a paperweight since its airworthiness cannot be restored and it cannot even be taken to E-LSA because it is no longer airworthy. You may get away with it, but someday, someone won't and it may be a $100k mistake.