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Posted by DingoII | Aug 27, 2021 @ 12:19 PM | 20,983 Views
2.5 years ago I bought Vector Board sheets in 1.5 mm and 4 mm thickness with an intention to build a model from this material. Well, it took me a long time to get enough pluck for it, I am a balsa builder .

The model is based on the Ayres Thrush and intended as a "technological demonstrator", mainly for testing the material processing, and structure design and sizing.

The wingspan is 720 mm, weight 160 grams, uses Dualsky XM2221 kv2200 motor. 6x4 prop and 2S power, plan in PDF attached.

My conclusion is to continue with the VB .

...Continue Reading
Posted by DingoII | Jul 20, 2021 @ 12:59 PM | 16,234 Views
This model aeroplane was conceived when I saw an article about a robbe Silvermöve (Silver Gull) in the German aeromodelling magazine FMT. The original kit from '70 was based on the Schleicher K-11 motorglider.

I downloaded the K-11 sketch from the Alexander Schleicher site ( (https://www.alexander-schleicher.de/en/flugzeuge/k-11/) and designed my own model in the 1:6 scale around it using the QCad software.

Wingspan - 2.2 m (86 in)
Weight - 1200 g (42 oz)
Wing loading - 30 g/dm2 (10 oz/sqft)
Wing airfoil - Selig S3021
Tail Airfoil - Drela HT13
Drive - Phasor 15-4, 9.5x5, 2S1500
Controls: Rudder, Elevator, Motor, Ailerons, Spoilers

I did not make the build log - I could not decide which forum to post it to

Jan
Posted by DingoII | Nov 01, 2020 @ 12:40 PM | 7,980 Views
The rules for organizing a man-on-man contest require that (citation from F5J sporting code): … the composition of Groups should minimize the situation where any competitor flies against another many times.

On our air fields it is likely the most frequent question - why do I have to fly 4 times against a pilot X? And adding, that the pilot X always gets 1000 while the other guys I do not meet with at all.

While I am convinced that the flying order (a term from the F5J rules) has a very little influence on the total score board, any improvement in the flying order matrix could make more people happy and therefore the contest more enjoable.

I spent some time over this issue and here is the outcome:
- problem and solution description in the pdf file
- excel (with macros) for calculation in the zip file

I would appreciate any comment/discussion.

Thanks, Jan
Posted by DingoII | Oct 31, 2020 @ 09:50 AM | 9,639 Views
Sometimes I need to refer back to my builds and comments on them. So this post is only for making the thread location easier.

Mig-15 EDF 69 mm: https://www.rcgroups.com/forums/show...out-1-10-scale

FJ-1 Fury EDF 30 mm: https://www.rcgroups.com/forums/show...Christmas-Fury

Su-25: Frogfoot EDF 50 mm: https://www.rcgroups.com/forums/show...27181-Frogfoot

E-Slite: https://www.rcgroups.com/forums/show...081-E-Slite-V2

Arado 96: https://www.rcgroups.com/forums/show...%28Avia-C-2%29
Posted by DingoII | Aug 13, 2017 @ 03:50 AM | 5,504 Views
I have been fascinated by the EDF for some time. I came across the EDF just few months ago when I "impulsively" added the DuraFly Vampire to my shopping cart at the Hobbyking site.

I did some bits of the EDF theory (please see it attached) during my holiday (cannot just swim and drink a do nothing else ;-) ) and then also measured the Vampire performance:

Flying at full throttle (interleaved with gliding) gave 4.5 minute of powered fligth. Recharged 2610 mAh into 4S-2650. This gives about 33 A, or 520 W of input power.

Max. speed measured by GPS telemetry was about 100 km/hr (scattered between 93 and 113 km/h in several passes). The landing speed was about 27 to 32 km/hr.

Then I devised a simple U-tube differential pressure gauge. It is just a piece of tubing taped to a vertical scale. The ends of tube are then introduced into the location od interest (please see the pictures). The pressure difference across the impeller measured at full throttle was about 180 mm of water column, without the access hatch is was just about 60 mm.

Well, all this data fall within the expected range of values, and although I would not expect them to be 100% accurate, seem to confirm that the theory works.

Thanks, Jan