Tiger Moth

[plug&fly]

Will a 12*6 prop be an overkill for this motor?
http://www.jethobby.com.sg/cgi-bin/e...1&idx=1&gid=12

Not if you use a 2cell lipo. Not for 3 cells. However, down propping would not lead to less overdrawing your batts. I'd say don't go over 11 x 5.5. on 2 cells. On 3cells go for 10 x 4.7 or 9 x 6. I had used these 2 combo on my camel with much success. On my ol'Moth I used 10 x 3.8 (3cells)and 10 x 6(2 cells) hyperdrive with equal success. Just remember it is a tigermoth not a 3D monster.

BTW a ceramic container can be anything from your rice bowl(not the plastic type) or a vase. I use an old ceramic teapot. There is no difference from the ceramic container or the lipo bag; both serve the same purpose.

[JieZ]

Not if you use a 2cell lipo. Not for 3 cells. However, down propping would not lead to less overdrawing your batts. I'd say don't go over 11 x 5.5. on 2 cells. On 3cells go for 10 x 4.7 or 9 x 6. I had used these 2 combo on my camel with much success. On my ol'Moth I used 10 x 3.8 (3cells)and 10 x 6(2 cells) hyperdrive with equal success. Just remember it is a tigermoth not a 3D monster.

BTW a ceramic container can be anything from your rice bowl(not the plastic type) or a vase. I use an old ceramic teapot. There is no difference from the ceramic container or the lipo bag; both serve the same purpose.

How does the pitch of the prop affects the plane?speed?And the size(inches).

Just broke my prop today due to hard landing.Got no props left except the 12*6.Didnt know 2cell lipo can power this bird.I've got one 7.4v 1900mah,two 11.1v 1300 mah , one 11.1v 1050mah.So should i use 10*4.7 so as to strike a difference between prop size?

Oh ya.My tiger moth is more balanced now after i added some weights.

[Ghostfit]

I had one of each donkey years ago.

You reminded me of those days !

The whole PFW morning sky just filled with Tiger moths of all sizes and colors !

Ahhh ! ...pure bliss !





...remember our Tiger moth lamp-pole lamba ?

[Tony]

How does the pitch of the prop affects the plane?speed?And the size(inches).

The pitch of a prop is (technically) is the distance the prop will travel in a single revolution. Therefore an 8 in pitch is supposed to travel 8 inches in a single revolution and a 6 inch pitch prop is supposed to travel 6 inches and so on. In the real world, it doesn't because of many other variables but you get the general idea.

A higher pitch prop there will (all things taken normal) will place a higher load on the motor as it tries to claw forward a longer distance with every revolution than a lower pitch prop. So the first effect is that a higher pitch prop will lead (again all things taken normal) a higher current draw from your cells than a lower pitch prop for a given diameter.

The above is for a perfect world. In the real world, there is a whole heap of other factors that come into play. So you may or may not get an increase in airspeed when you use a higher pitch prop vs a lower pitch prop for a given diameter.

It is normal that to increase the pitch, one has to reduce diameter to compensate or vice versa. It all depends on what you want the plane to do. High speed racing aircraft rely on high reving shorter props with high pitch for speed but poor climb. Gliders need larger diameter props with lower pitch for higher climb (thrust) at lower speeds. Aerobatic planes are somewhere in between.

I used to build tiny House of Balsa sport scale planes. Powering them first with Cox TD 0.49 engines. These reved like there was no tomorrow on tiny 6 in props. This engine/prop combo were characterised by the singular lack of thrust but would produce lots of airspeed. The planes would fly like bats out of hell but would slow down drastically during turns. Slow them down too much and they'd literally fall out of the sky.

With the coming of age of electrics, I built the same planes but this time with S400 sized brushless turning 8 or 9 inc props. The higher efficiency of the larger diameter props turning at more efficient rpms produced heaps of thrust and allowed the planes to fly at slower speeds and yet their performance was improved as they did not slow down much during maneouvres. Big time transformation in the flight characteristics. Planes were the same but it was the improved power/prop combinations that did it.

Just a simple example to show you how the pitch/diameter affects your planes flight characteristics.

[JieZ]

The pitch of a prop is (technically) is the distance the prop will travel in a single revolution. Therefore an 8 in pitch is supposed to travel 8 inches in a single revolution and a 6 inch pitch prop is supposed to travel 6 inches and so on. In the real world, it doesn't because of many other variables but you get the general idea.

A higher pitch prop there will (all things taken normal) will place a higher load on the motor as it tries to claw forward a longer distance with every revolution than a lower pitch prop. So the first effect is that a higher pitch prop will lead (again all things taken normal) a higher current draw from your cells than a lower pitch prop for a given diameter.

The above is for a perfect world. In the real world, there is a whole heap of other factors that come into play. So you may or may not get an increase in airspeed when you use a higher pitch prop vs a lower pitch prop for a given diameter.

It is normal that to increase the pitch, one has to reduce diameter to compensate or vice versa. It all depends on what you want the plane to do. High speed racing aircraft rely on high reving shorter props with high pitch for speed but poor climb. Gliders need larger diameter props with lower pitch for higher climb (thrust) at lower speeds. Aerobatic planes are somewhere in between.

I used to build tiny House of Balsa sport scale planes. Powering them first with Cox TD 0.49 engines. These reved like there was no tomorrow on tiny 6 in props. This engine/prop combo were characterised by the singular lack of thrust but would produce lots of airspeed. The planes would fly like bats out of hell but would slow down drastically during turns. Slow them down too much and they'd literally fall out of the sky.

With the coming of age of electrics, I built the same planes but this time with S400 sized brushless turning 8 or 9 inc props. The higher efficiency of the larger diameter props turning at more efficient rpms produced heaps of thrust and allowed the planes to fly at slower speeds and yet their performance was improved as they did not slow down much during maneouvres. Big time transformation in the flight characteristics. Planes were the same but it was the improved power/prop combinations that did it.

Just a simple example to show you how the pitch/diameter affects your planes flight characteristics.

So if i want to counter wind i need more thrust?

[Sunstorm]

Yes, in a way. If you want to overcome strong winds, more thrust (e.g. more throttle helps) Sometimes there are cases of very light airplanes - e.g. pico tiger moth staying still or flying backwards when they go against strong winds.

Wanna ask how come you need to use full throttle so often as written in your first post?

[JieZ]

Yes, in a way. If you want to overcome strong winds, more thrust (e.g. more throttle helps) Sometimes there are cases of very light airplanes - e.g. pico tiger moth staying still or flying backwards when they go against strong winds.

Wanna ask how come you need to use full throttle so often as written in your first post?

Oh.Mine is the 400 version.

I full throttle most of the time because

1.Nervous
2.Counter wind
3.No throttle management(piloting skills)

Still noob in throttle manangement and landing.

I want to ask how come whenever i land,the bird plots onto the grass and flipped.Is it because i applied too little/much power or is it the grass.Whenever i land,I cant seen to pull the stick up.Like got no effect.Is it too little throttle?

[Tony]

A case of Newtons law in action ie. a body in motion wants to continue to stay in motion. Land a plane with small wheels in grass.......friction from grass or grass blades catches small wheels so wheels want to stop...........but plane wants to go on. Result - a nose over. Solution - land on smoother surface eg. paved road or use larger diameter wheels (if possible) or remove undercarriage and land on belly. A common issue with tail draggers. Less so with trikes.

[Sunstorm]

Oh.Mine is the 400 version.

I full throttle most of the time because

1.Nervous
2.Counter wind
3.No throttle management(piloting skills)

Still noob in throttle manangement and landing.

I want to ask how come whenever i land,the bird plots onto the grass and flipped.Is it because i applied too little/much power or is it the grass.Whenever i land,I cant seen to pull the stick up.Like got no effect.Is it too little throttle?

Man you need to fly electric gliders No throttle management at all!

When you land make sure you are slightly nosed up - aka you rem the way real planes land? Also ensure that you are almost at stall speed.

Also need to have a bit of throttle, but you already say your throttle management is no good, so what can I say?

Practice more, then... go woodlands more to practice on the road landings.

[JieZ]

Man you need to fly electric gliders No throttle management at all!

When you land make sure you are slightly nosed up - aka you rem the way real planes land? Also ensure that you are almost at stall speed.

Also need to have a bit of throttle, but you already say your throttle management is no good, so what can I say?

Practice more, then... go woodlands more to practice on the road landings.

Haha.Perhaps one day i'll try Gliders.For now,I think i'll swap the wheels to one that have larger diameter and keep practicing.

[romihensem]

hmmm

heres a good take off and landing training video. it helps me alot during my 3d days...

http://young99.net/images/Videos/3DCLINIC06a.wmv

http://young99.net/images/Videos/3DCLINIC06b.wmv