Slow Flying Concorde

[AstroBoy]

Nice Benson & Hedges, bought them at the duty-free in Dubai???

Seriously Dennis, can't wait to see her up in the clear blue sky soon!

[DennisP]

No Lah... had to buy a packet (one only.. ) in Dubai.....

[DennisP]

As I have today and tomorrow off from work, pressed on to get the Concorde as complete as could be. Servo's, motors, propellers control linkages all fitted so just need to make that "Chuckie" to validate the CG position.

Went to the store room for some Depron to fabricate the Chuckie and as old mother hubard would say the "the cuboard is bare", so I shall have to go to the smoke (city) to get some more which will be in about a weeks time as I rarely go to the smoke.

So there we are guys from a paper dream to a model Concorde, which seemed to take for ever to build, but this is expected when one is scratch building from plans. It is always good to review what you have achieved or not as the case may be or what you could have done better....

In the case of the Concorde, I still need to improve my finishing and try to get that good finish with minimum weight increase, I do have some ideas on this already.. As for the design itself seems OK with the few modifications that I had made, if any of you do decide to make this model then I would strongly recommend the balsa trailing edge that I used between the wing and the elevons which was used for the motor plywood mounting plate alignment. I say this as my motors were dead square as they should be but I suspect without some sort of alignment reference you could be in trouble. It may only save a few grams but with the moments involved in the case of this model I wish that I had hollowed out the tail cone, as there is an awful lot of weight up the rear with the two AXI's.

Other than that from initial base line checks the battery will probably be located in the area just in front of the wing, this will be confirmed once the Chuckie finalises the CG position.

I suspect that you do not really appreciate the size of the Concorde, so here is a picture of MOHA holding the bird. I hope that this thread has been of use / interest to all who have followed it.

Now I must clear area 617 up of the Skunk Works and start a long overdue 2 x EDF project, as always this is another un-conventional build in every sense of the word, so I will provide you guys with some information as the beast takes shape.... ......Then of course comes my all time favourite the TSR2 and that is bigger than the Concorde... I just love challenges......

So many models to build so little time......

[Jcho]

Nice.....when are you going to maiden it?

[DennisP]

Thanks Jcho, once the CG issue is sorted then we shall be ready to rock & roll, will keep you updated

[AstroBoy]

Dennis! I'm absolutely impressed with your building skills on this Concorde! To see it in it's full livery tonight, and the concorde is so beautifully made,yes, from just a paper dream into what you see here!

And i do hope that somebody else out there is willing to give a go at building this concorde. But i guess everyone is waiting for THE day The moment of thruth so to speak.

Well done Dennis! 3 Cheers for Dennis!

Hmmmm.... i can hear the wherring sound of the B777 turbines in the distance!

[DennisP]

Thanks for the kind words, I have no doubt in my mind it will fly. Everything flies even the late DH Trident which went supersonic in the 60's scary. It also fell out of the sky backwards when it stalled.

I have sought the help of a aerodynamist in the UK for his advice on the CG which will make a good double check of the CG location.. The big issue with the Concorde wing is that it is not a regular triangular delta which rather if I dare say it screws the normal CG calculations up.

I did however find a CG program from a German aerodynamist which gets near to the requirements in that you can define a different delta wing profile. The results are attached in the pictures below, it is worth comparing this and the original calculations (1st picture) and it can be seen the wing profile does affect the CG.

[AstroBoy]

So it's between 370.0 and 388.6? Am i reading that attached graph correctly Dennis? My drawings showed 375 is it close?

[DennisP]

Yes, but from the trailing edge, leading edge of the delta is 110 mm in front or by F1 and not F2, so the effective CG is further forward. This seems to tie up with the 4 x EDF Concorde made by Chris Goulds who also remarked how forward the CG was.

Mind you having the CG further forward is another potential problem as it will mean the Li-Poly is going to have to move as far forward as possible. On the real Concorde the CG was moved dramatically by moving the fuel around the airframe, as far as I can acertain they moved the fuel to back once airbourne and getting up speed, not that this is and issue in the case of the model. I am sure that it will never reach Mach 2.0, as we shall be lucky to see Mach 0.0012

Still the ghuru's will provide the answers and the Chuckie will confirm same I am sure, that way we can be relatively sure of a not too dramtic maiden fright.

[AstroBoy]

My Goodness! Oh Dear! The CG on the drawing is completely wrong!

I will churn out the concorde chuckie drawing and the TSR-2 out for you in a jiffy!

[DennisP]

No problem and no worries, thin delta's are velly strange which is why I wanted to be really sure of the CG both from a theory point of view and also practical with the Chuckie.

[mechplas]

Dennis: .................................................. .................................................. .................................................. .................................................. .................................................. .................................................. .................................................. .................................................. .................................................. .................................................. .................................................. .................................................. .................................................. .................................................. .................................................. .................................................. .................................................. .................................................. ................

SPEECHLESS!

[DennisP]

"Chuckie"

Astroboy kindly produced a 50% reduction of the Concorde plans and "Chuckie" was born in just over 30 minutes. The objective of "Chuckie" is to determine the actual CG for the slender delta wing shape of the Concorde, one test was made and the MOHA was far from happy about "Chuckie" being hurled across the living room so testing had to stop.

A Chuck glider of the model is a good way to determine the CG of a strange footprint model and for the time it takes to make saves that everso nice real model you have just made.

[DennisP]

More fun with "Chuckie"....

I have now managed to perform some tests, I can only say this model has a wide range of CG. All measuremnts are from the tailing edge (more accurate)

Best position 145 mm from TE
Tail heavy 135 mm from TE (definate climb and stall)
Best nose heavy 155 mm from TE

So since the "Chuckie" is 50% of the real model the CG should be 290 mm from the TE +/- 5mm.

I plan to do further tests just to validate the above as the ceiling fan was on and that would provide a down force on the wing (oop's)...... now when is the MOHA going out again.....

[AstroBoy]

Thanks Dennis, original drawings showed CG to be 271mm from TE, and i have just updated the drawings to reflect the 290mm from TE, thanks for testing out the chuckie, please go downstairs to try the chuckie lah!

Once you've maidened the bird, let me know the CG range and i will update the drawings and post up here as "FINAL Post-Maiden Plans".

Keep up the great work Dennis, always enjoying your build