The main landing gear is also shown in the document called (in case of your - Manufacturer - subscription) Manufacturer - 3D Model - PDF Format. Please note that the bending radius close to the fuselage was made much larger on the model compared with the drawings. This is in accordance with the real airplane and also in accordance with the minimal bend radius of the material used (aluminium alloy 2024).
Please find the drawing of tail wheel leg attached.
In contrary to the local photo gallery, I had to replace the original glass fiber leg with 4mm thick aluminium alloy leg. Due to the strain I even had to add a second half length 4 mm layer. See the photos attached.
A simplified drawing of the tail wheel construction is included in the Manufacturer - 3D Model - PDF Format document. I believe the folowing images would give you much better understanding of the construction used.
If I understand it the rear landing gear had a update because the construction was not durable/strong enough to suport the landing weight of the plane. The main landing gear had a optical update not be cause it was not strong enough ?. I compaired the zise and the weight whit orther planes I know that work OK, What I see here is that for its zise the weight could be lower. Do you have any sugestions on points on the plane were you did find out that you could reduce weight and strenght ?
And did you had to use extra weight to get the plane to balance ?
Last edit: 4 years 5 months ago by Beverik. Reason: did not reed the information good
in reality, the reason for replacing the glass fiber landing gear with aluminium alloy was due to my inabilty to make the glass fiber parts properly, I have limited experience in working with this kind of material and didn't manage to make them right.
The "optical update" (bending radius) of the main landing gear was given by the minimal bending radius recommended for the aluminum alloy of 8 mm thickness. Also this radius is closer to the radius used on the real airplane. The second aluminium alloy layer of rear wheel leg was added to suport the landing weight of the plane.
In terms of weight, you're right, the plane of this size can be built lighter. The reachable weight could be about 35 kgs. To be honest, the prototype shown on this web pages was actually intended to be built heavy. I wanted to test the flight performance at this load. If the plane can fly at 50 kgs, it would fly at 35 kgs as well. Also, it was sort of test of the performance of the engine used. No additional weight was used to balance the CG. Personally, I prefer models with weight that makes them flying similar to the real planes. The performance of 35 kgs model of this size is almost unlimited as opposite to the real airplane. In my opinion the flying performance of 50 kgs model is more realistic. Nevertheless, please consider this as my personal preference only, I'm aware that in general, the modellers prefer as light models as possible.
The weight of 50 kgs is the take off weight, i.e. with the tank filled with gas. The weight can be saved in several ways. The numbers below are just my best estimates and should be considered as guidelines only for areas of possible weight savings:
- 2 strokes engine can be used, 4 stroke engines are heavier in general (- 2-3 kgs)
- 1 litre tank instead of 2 litres used (- 1 kg)
- painting - ordinary car painting was used, about 3 litres of different paints and filler (-1.5 kgs)
- covering could be made by using heat activated polyester covering film (Oracover, etc.) which doesn't need painting (-0.5 kg)
- Wing covering was made using plywood, it can be done using balsa (- 2kgs)
- horizontal and vertical stabilizer were made as removable using aluminium joining tubes. The thickness of the stabilizers were made to hide the servos completely. If the stabilizers were made as non removable simple 10-12 mm thin panels with elevator servos placed in the fuselage the weight could be reduced significantly (- 1 kg).
- The construction of the fuselage is robust, mainly the rear part, the diagonal struts could be smaller and lighter (-1 kg)
- the engine cowl is home made glass fiber part, the thickness is about 1 mm, could be lighter (- 0.5 kg)
- landing gear could be done from glass fiber (- 1 kg)
- The main landing wheels could be lighter (- 0.4 kg)
- The rear wheel leg could be done from fiber glas (- 0.2 kg)
- the batteries used were 2x8Ah for receivers and servos, lower capacity batteries can be used (-0.4 kg)
- two silencers were used for a 4 stroke engine, while only one common silencer is normaly used for 4 stroke engines (-1kg)
- less powerful and lighter servos can be used for lighter model