O.K. guys... some answers:
1. Engine is mounted directly on firewall. I have tried to use some compensators, but from my experience direct mounting can work out better with compact fuselage construction (and WACO is one of them). Of course, firewall is modified (greater thickness) with another wooden plate (original seems to fragile to me), then both sides are laminated with thin glass wool and epoxy. I have not chosen hydromount, because i've needed some extra space for ignition chip, ignition battery and a smoke system pump. My theory is that everything that belongs to engine electric support, should stay far ahead from receavers, aerials, ...
2. Oratex will do a great job. I have used transparent one and then painted with 2-K lack.
3. Radial engine was my wish too
. But i couldn't find any suitable petrol engine that would go under cowl. Recently I've seen a new MOKI 150 ccm radial and perhaps this model would suit everyone needs. Other possibility was to use a classic methanol radial engine, but since i'm more petrol lover, i have abandoned the idea. If you can mount a radial, the plane would look as good as real one
. Other possibility is use of boxer engine. But with need of a HP in reserve, engine should have at least 7-8 HP, that means ca. 70-80 ccm boxer. Boxer works fine, but i didn't want to cut sides of my cowl to make some room for spark plugs. One cyl. engine was a good compromise to me.
4. For smoke system, i've chosen a Slimline Show Time Pro. The battery is integrated and a pump el. motor is speed regulated. But an ordinary pump will do a job just fine. My oil tank has 0,5 l vol. I would suggest, that tail surfases that are open (tail wheel section, rudder/tail wings joint section, ....) should be protected with thin layer of transparent lack or better with epoxy. Oil fumes from smoker are condensing quickly and they can damage wooden sections on tail.
5. Flight computer.... sounds so Sci-fi heh ... Purpose was to have a central operating system for independed servo supply, independed servo control (pulse modulation check), double battery supply and duble receiver control. I have always wanted to eliminate a possible errors from installed equipement, so with this set of control there is only one mistakable factor. You've got it right. Me!!!
6. As for installed equipement:
Servos: Ailerons: 2 x Hitec 5745MG digital (yes i know, too strong [>:])
Rudder: 1 x Hitec 5645MG digital, 1 x Hitec HS 925MG for tail wheel
Tail wings: 2 x Hitec 5645MG digital
Throttle and Kill switch: 1 x Hitec HS 925MG each
CPU: Emcotec DPSI-TWIN, DPSI-ICE
Power supply: 2 x Longgo LiPo 3300 mAh Safe
Recievers: 2 x Multiplex RX-9 Synth DS IPD
7. Reynolds... theory from my university: "The Reynolds number is the ratio of inertial forces to viscous forces and is used for determining whether a flow will be laminar or turbulent. It is the most important dimensionless number in fluid dynamics and provides a criterion for determining dynamic similitude. When two similar objects in perhaps different fluids with possibly different flowrates have similar fluid flow around them, they are said to be dynamically similar...."
But there is one little problem. Determination of number is more complex for outer flow (easy for tube flow theory) theory. And aircraft is an object of outer flow theory. Since a normal Re calculation depends strictly from fluid velocity (aircraft section speed), characteristic dimension, fluid density and dynamic fluid viscosity, calculation should be easy for elementary objects; not aircraft !!! Normaly we use also Euler number for macroscopic calculation (plus
Pr number in model scaling), sufficient calculation comes across only with use of microscopic observation of laminar flow (with Navier-Stokes) or better observation of laminar/turbulent border.
All that is just fine when one calculates a stationary flow status. As for aircraft or better aerobatic aircraft models (NON stationary flow status), we use Re simply to determine approx. flying characteristics of an model plane from his big brother. That all depends from a aircraft scale (normally bigger is better; mostly but not always) and of course from right wing profile construction. Therefore the similarity with real aircraft can be achieved even at totaly different Re numbers, mostly with use of right wing profile.
There is a very good model aircraft aerodynamic theory in book Aerodynamik des Flugzeugs (Amazon, ...).
8. Flying with ZDZ80 came out just fine. It has some HP in reserve (so i used 24-12 prop for low turn speeds, but better prop efficiency). Take off is very smooth, due to a very efficient rudder. Landings are not so tricky, but i had a few "bums-a-daisy" at first[:'(]. Plane is very inert and main springs are doing their job...
You will find some pictures and a first flying movies at
http://s54.yousendit.com/d.aspx?id=3...N1N52Q3K5HLWV5 (max. 25 downloads)
sorry, some pics are bad...
I hope that you guys will be satisfied with model as i am.
Marko