1914 Blackburn Monoplane Type I

Status: Undergoing Maintenance
Number of Views: 311

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Date added to fleet:
Total Flight Time:
Total Number of Flights:
Typical Flight Time:


62.0 in (157.5 cm)
Wing Area:
685.0 sq in (44.2 dm^2)
Weight (less battery):
65.0 oz (1843 g)
Wing Loading:
13.7 oz/ft^2 (41.7 g/dm^2)
Cubic Wing Loading:
Full-Scale Wingspan:
38.0 ft (11.6 m)
Center of Gravity:
it was balancing out on the main spar




Build Thread:


1/6 scale

Currently being converted to electric.

Motocalc's opinion of the proposed drive system:

MotOpinion - Blackburn Monoplane
650ft above Sea Level, 29.92inHg, 57°F

Motor: Purple Power PPO-5055-400; 400rpm/V; 1.6A no-load; 0.031 Ohms.
Battery: Kokam 2100SHD (20C); 4 series x 2 parallel cells; 2200mAh @ 3.7V; 0.0114 Ohms/cell.
Speed Control: Generic Brushless ESC; 0.006 Ohms; High rate.
Drive System: Generic 12x6in Prop; 14x8 (Pconst=1.31; Tconst=0.95) direct drive.
Airframe: Blackburn Monoplane; 730sq.in; 98.1oz RTF; 19.3oz/sq.ft; Cd=0.067; Cl=0.47; Clopt=0.67; Clmax=1.14.
Stats: 46 W/lb in; 40 W/lb out; 21mph stall; 28mph opt @ 88% (39:22, 86°F); 33mph level; 351ft/min @ 8.3°; -309ft/min @ -7.3°.


MotoCalc was unable to determine a throttle setting for hands-off cruise airspeed, so the best lift-to-drag ratio airspeed and throttle setting will be used instead.
Inability to determine a throttle setting for an airspeed usually means the model is not capable of reaching the required speed with the given power system, or the airfoil information has not been specified correctly.

Possible Power System Problems:

The full-throttle motor current at the best lift-to-drag ratio airspeed (13.1A) is lower than the motor's maximum efficiency current (27.3A). A higher current level would improve system efficiency.
Current can be increased by using more cells, a larger diameter or higher pitched propeller, a lower gear ratio, or some combination of these methods.

Power System Notes:

The voltage (14.2V) exceeds 12V. Be sure the speed control is rated for at least the number of cells specified above.

Possible Aerodynamic Problems:

The static pitch speed (41mph) is much less than 2.5 times the stall speed (21mph), which may result in reduced performance at typical flying speeds and a low maximum speed. This situation is usually acceptable for an electric sailplane.
Pitch speed can be increased by using a higher pitched and/or smaller diameter propeller, a higher cell count, or some combination of these methods.

Aerodynamic Notes:

Due to some of the potential problems listed above, this model may require an experienced pilot.
The static thrust (60.7oz) to weight (98.1oz) ratio is 0.62:1, which will result in short take-off runs, and no difficulty taking off from grass surfaces (assuming sufficiently large wheels).
At the best lift-to-drag ratio airspeed, the excess-thrust (15.8oz) to weight (98.1oz) ratio is 0.16:1, which will give good climbs and acceleration. This is a good in-flight thrust to weight ratio for a basic trainer.

General Notes:

This analysis is based on calculations that take motor heating effects into account.
These calculations are based on mathematical models that may not account for all limitations of the components used. Always consult the power system component manufacturers to ensure that no limits (current, rpm, etc.) are being exceeded.

From original owner:
it was balancing out on the main spar even though there are black marks under the wing that I originally thought were the balance points. I did check it with the engine in it as you asked. Let me know when you finally get it ready to fly as I'm interested in how she flys. Take care and thanks, Shoo

Yeah, won't hurt to start at the spar with the balance and go from there, I'd think. You may have to move it around a bit, she was just a tad nose heavy when I picked it up with my thumbs under the spar. I would imagine this plane will draw a crowd when you bring it out at the flying field, it is pretty unique. Talk to you soon, Randy


1914 magazine articles:

Pics of the original:
more pics here: http://flyingmachines.ru/Site2/Crafts/Craft29825.htm



specs of original: http://www.flightglobal.com/pdfarchive/view/1914/1914%20-%200260.html

Flight Duration Histogram


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