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Some technical aspects of the Raptor MK
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Some technical aspects of the Raptor MK-1

Length 14.22'
Wing Span 21.4'
Canard Span 9.4'
Empty Weight 520 Lbs
Useful Load 380 Lbs
Fuel Capacity 32 US Gal
V stall 50 Kts
V max 245 Kts @ 110 HP
V ne 270 Kts
Stressed 12 G's
Fully Retractable Gear
Forward Hinged Canopy
All Composite Construction
Engine Option 1 - VW Type 4 (2600cc)
Engine Option 2 - Corvair 3100cc
HP 80 - 140
Best LD - 120 Kts
LD - 25:1
Min Descent - 90 Kts @ 410 ft/sec

I have up until now done an initial weight an balance exercise and determined that the ideal C_G to be at FS76.  The Neutral Point is located at FS 79.5. I have also analyzed the Eppler1230 airfoil against many others, but none have the desired L/D polars as it.  The Roncz R1145MS was also analyzed and proves to be the best so far for use as a Canard.

Here are the polars for the estimated Reynolds equation:

 

At this stage I am still having difficulty in determining the shift in NP due to the increase in C_l of the canard.  I used the formula as suggested by Hollmann, there seems to be an unusually large shift of the Center of Lift much beyond the CG.

Example:

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CG @ 76"

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NP @ 79.5"

Coefficient_ofLift 0.30 0.60 1.00 2.00 2.20 2.80
Center_of_Lift 87.79 86.57 81.41 68.52 65.94 58.21

The Canard needs to produce C_l 2.8 to maintain lift at 65_Mph.

V_Stall V_Max
65_Mph 240_Mph
Canard 2.84 0.21 C_l
wing 0.93 0.01 C_l

Lift ditribution

Equipped CG @ FS

74.5
CANARD
MAC@FUSELAGE STATION 22.0
AREA  (sq. ft) 9.75*110 in 7.5
MOMENT FROM CofG 52.5
LIFT (lbs) 239.8
LOADING (lbs/sq.ft) 32.0
WING
MAC@FUSELAGE STATION 94.0
AREA   (sq. ft) 66.3
MOMENT FROM CofG 19.5
LIFT (lbs) 647.2
LOADING (lbs/sq.ft) 9.8

More to come soon......!

I will appreciate any suggestions.

 Last updated13-09-04 04:16 AM