Slow Flying Concorde

[DennisP]

After a long delay due to reams of work at the office and having to go outstation the Concorde is back on the bench. The underbelly of the wing is complex, loads of curves and angles so one awful lot of sanding to get things correct. As the meshing of the belly pan to the fuselage will be difficult to achieve once the wing is in place two strips of 5mm Depron were taped to the underbelly to get a sort of mini wing to get the shaping correct. One more final sand with 400 and 600 grit and then we can put the fuselage aside and get into that big delta.

As I advised in another thread I now have Reflex XTR version of the model so I have been test flying the model at the field to see how it behaves with two 6 x 4 propellers. Speed wise similar to the F-15 of AstroBoy's no real nasty tendances except a marked pitch up from low throttle to hitting the firewall, as expected it will fly slow at very high alpha's looks very impressive to say the least.

Here is a picture of the underbelly located in the fuselage.

[AstroBoy]

WoooH!!! Dennis, I'm getting more excited about your concorde!
Yes, the belly looks so scale now!

Did you import/model the concorde .dwg files into XTR for flight simulation? If so, that's very interesting! then my future plane drawings could be input into this programme and we can test-fly virtually and tweak the drawings before actual build/flight, YeY!

[DennisP]

Hi AstroBoy, actually I cheated well sort of, I downloaded a XTR Concorde from the German downloads site and then used the Reflex plane maker to remove the U/C. and add propellers rather than the gas turbines it originally had. I still have not managed to get it 100% but we are working on it. Some of the parameters are well beoynd me at the moment

The Reflex plane maker software uses photographs of your model as the base line you then add a lot of points (ex the drawing) and add all the other bits. At first it was rather daunting but I decided to do simple changes first and then it all falls into places, well sort of....

[DennisP]

Hi AstroBoy, I put the bird on the scales, the fuselage including the fin and the dummy wing tipped out at 132 Grams while each wing panel is 58 grams so we are looking at 238 grams at the moment without radio, servo's and motors. I have a tempatation to go to a single panel wing to save 58 grams in my world that is only 2 oz which is not a lot, neither is an airframe weight of 8.4 ounces. Once I have achieved some more assembly of the bird I shall punch the numbers into MotoCalc to see what we can expect...

[AstroBoy]

Dennis, just for weight comparison purposes only, my foam F-15 AUW with 1250mah 3S flight lipo battery is 631 grammes, wing area i'm sure is a lot lesser than your concorde, and the concorde being a delta wing, it will float and fly well, your equipment weight with flight battery should be in the region of 200~250 grammes, i think So total AUW with flight battery is still about 500 ~550 grammes, i think, again!
I feel very good about the success of this bird

[DennisP]

Thanks AstroBoy, information noted, based upon experience the raw Depron airframe after painting and final gluing will rise by 25% to 30% in total weight. As there will be two AXI motors suspect I am going to need a 1,700 or even a 2,000 mA pack so there is more weight to be lugged around the sky, or attracted to the earth by Mr. Gravity..

I will do a more detailed analysis tonight using MotoCalc, so that all those small items that add 5 grams here and there are included, servo's, extension leads, motor leads (heavy stuff), RX and connectors. It is amazing how much this little lot adds to the weight to the airframe.

However I still reckon I should be just under 600 grams all up ready to rock and roll.

[DennisP]

Hi AstroBoy, OK I have done the measurements from the drawings and plugged the numbers into MotoCalc. FYI the wing area is 208,161 sq.mm or in my world 323 sq." this is using the standard convention of the wing area also includes the fusleage area right up to F1 if you extend the wing profile through. Using 2 x AXI 2208/26 motors and Castle Creation ESC's we get 130 watts of suck from the pack spinning APC 6 x 4 propellers at 13,513 rpm. This translates into a rate of climb of 1,221 ft/min and firewall runtime of just over 9 minutes using a Kokam 2,000 mA pack, could possibly use a smaller pack and save a few grams. Stall speed is high at 18 mph but I have set the weight to 600 grams, ah yes the static propeller speed is 51.2 mph or in your units 23 mtr/sec. So all I have to do now is load this lot into Reflex and we see how the bird is really going to fly...

[DennisP]

And for those readers who do not care about all the B*** S*** above, I have now received the final proof of the decals for the model. There were three colour schemes for the British Airways Concordes the first after the merger of BOAC and BEA (who are they you are saying.... ) this scheme had a red top to the fin which I like, you can see the missile then came the blue fin with some silly coat of arms followed by the current British Airways wavy flag thingie. So needless to say I chose the first which has the least documentation making the graphics a real nightmare for the guys in the USA. They have as always come out trumps and done a good job so it is down to yours truly to finish the bird off and get a good finish on the Depron to do justice to the decals.

[AstroBoy]

[QUOTE=DennisP]spinning APC 6 x 4 propellers at 13,513 rpm. This translates into a rate of climb of 1,221 ft/min ....
ah yes the static propeller speed is 51.2 mph or in your units 23 mtr/sec.[quote]

Dennis, the numbers looks deliciously FAST! I Love It!

[DennisP]

Umm thank goodness it is not greater than Mach 1, the Depron would melt Had a quick play with Reflex, loading the models construction parameters, umm had some fun and games here, it was like a bullet with stability of a drunken cat I am sure I have something wrong in those parameters that Reflex offers so I shall to on it so to speak. One observation that I have made is that a high alpha of say 20 degrees the drag kills the speed dramatically, nose down and you are back in business. It also seems sensistive on the elevator anymore than 18 degrees and boy you are in for the stall of your life complete with spins, thanks goodness it is a simulator there are more Concorde darts sticking out of the ground of Edgfield plaines than there were Concordes ever made. Still I am sure the obvious is staring me in the face as they say

[P4cm4n2000]

When will you be maidening the plane man Dennis? would be fun to watch...since most folks turn to the "Dark" side now flying Nitro........

[DennisP]

I suspect that at my current rate of progess I am still a few weeks away, especially as I have to go to the UK for 2 weeks in July. However if you just watch the thread you will see when the bird will be ready for that first moment into the blue yonder or a trip to Mr. Gravity land.

I never thought of oil burners being on the Dark Side , very good I like it, I like oil burners apart from the mess they get themselves into, and of course the wrath of the MOHA when it drops oil on the floor.

I have several other aircraft lined up after the Concorde is finished and these are all electron powered, 1 pusher (could be two if I search the store..!) and a twin EDF model. So I suspect I shall be on the grey side as I fly both..

[DennisP]

Out of interest here is a proof of the decals that I have had made for the twin EDF.....

[DennisP]

It is time to work on that wing..... , I have yet again deviated from the original plans as I was concerned of wing flexing especially the leading edges of the delta. So I am using MidWest 0.188" fiber tube as stiffeners and also for the original main spar, there is also the need for the grooves for the servo wires / extension leads and of course the power leads to the ESC's.

The same Dremel tool that was used to slot the tail cone for the fin is again used but with two different bits, a ball head for the fiber tubes and a straight router bit for the cable grooves. If you decide to follow this technique do make sure that you set the depth right , "been there done it" a perfect slot not with Concorde wing..

Here is the first photo showing the leading edge slot being cut, and at the end of slot.

[DennisP]

Here is photo showing the cables laid and some of the carbon tubes in laid over. Sorry AstroBoy another modification there is a small carbon tube laid in front of the servo groove, the idea is to act more of radiation deflector rather than add any strength. You can also see the router bits that I used.