New prject - DH Chipmunk

[david whiston]

Gents
not sure if this helps but on my Fuji, you have to really prime the motor before she will even think of firing , when I say really I mean to the point of petrol dripping back out of the carb, she then happily fires up a runs like a " Good un" most impressed as these are a powerful little motor. On the Fuji twin, it has automatic decompression buttons on each cylinder which aid starting,
hope that helps

[david whiston]

Looking at the photo's, it looks like you have easy access to the mouth of the trumpet?? I suspect that the previous owner stuck his thumb over the trumpet mouth and turned the engine over until she was wet ?? ( Of course the ignition switch is in the OFF) position whilst doing this,, then once wet , switch pon and give it a good flick and of she goes,,, well mine does ... hope that helps.

[richard armstrong]

Gents
not sure if this helps but on my Fuji, you have to really prime the motor before she will even think of firing , when I say really I mean to the point of petrol dripping back out of the carb, she then happily fires up a runs like a " Good un" most impressed as these are a powerful little motor. On the Fuji twin, it has automatic decompression buttons on each cylinder which aid starting,
hope that helps

thanks that's big help from someone who has experience of fuji engines

[richard armstrong]

quick question

i setting up the rx do i need to add aileron differential to the chippie is required?

and how much diff if required?


i have set it on the tiggie?

[Tony Collins 1073]

Hi Richard. Depends on the model but generally speaking about just under half the amount of the up going aeleron is a
good starting point for the down going one.
Tony.

[david whiston]

Oh and Richard
once you have done all the bits and bobs , re check the C of G just in case you moved / removed anything which might have been there to get the balance correct.

[richard armstrong]

Oh and Richard
once you have done all the bits and bobs , re check the C of G just in case you moved / removed anything which might have been there to get the balance correct.

thanks dave

thats a given i always do when i referb an aircraft

what are the C of G measurements for a chippie?

next project 1/4 scale Jodel Robin d400 that just need new batteries and engine check over

[david whiston]

try this
http://adamone.rchomepage.com/cg_calc.htm

unless someone actually knows what the Cof G is I would go for 25% of the chord ????

[richard armstrong]

try this
http://adamone.rchomepage.com/cg_calc.htm

unless someone actually knows what the Cof G is I would go for 25% of the chord ????

thanks

[chris-berry]

Richard, I wouldn't bother messing with the strobe lighting etc until you've flown the aircraft and made sure you're happy with it. I'm flying a 1/4 scale chippy and haven't put and diff on the ailerons. I wouldn't think diff is needed on a 5th chipmunk. As for the engine, just use your hand to choke and away you go.

I'm using 2 Sub c Nimhs directly into a spektrum rx. At 1/5th scale you're looking at about 85" span and probably sub 15lbs. I'd go for a single 3300 sub-c nimh and leave it at that.

Is it an Apache Aviation chipmunk and whats the weight?

Chris

[richard armstrong]

Richard, I wouldn't bother messing with the strobe lighting etc until you've flown the aircraft and made sure you're happy with it. I'm flying a 1/4 scale chippy and haven't put and diff on the ailerons. I wouldn't think diff is needed on a 5th chipmunk. As for the engine, just use your hand to choke and away you go.

I'm using 2 Sub c Nimhs directly into a spektrum rx. At 1/5th scale you're looking at about 85" span and probably sub 15lbs. I'd go for a single 3300 sub-c nimh and leave it at that.

Is it an Apache Aviation chipmunk and whats the weight?

Chris

chris thanks for the above info,

i dont know which maker the previous owner never gave the details as i went through a 3rd party, and the weight will be done once i get it put together and come to do the CofG, i will be bring it to one of the flyin for testing

whats your thoughts on using LIPO receiver packs with UBECsto reg voltage either to 5v or 6v depending on servos, 2 x 2000mah 20c pack in using sub c nmh packs?

http://www.hobbyking.com/hobbyking/stor ... ouse_.html

[chris-berry]

I know lots of people who use lipos as Rx packs. Personally I prefer Nimhs, have used them for years, never had any problems. Sub C sanyo 3300. Regular checking and load testing and so far ive never had a problem.

I wouldn't be too fussed about running 2 rx packs for the size and weight of model you have but each to their own.

I've just looked at the pictures you posted, it looks like a typical ARTF with the removable canopy/hatch. I'm guessing its a Blackhorse.

[Rob Buckley]

Use an A123 or LiFe battery rather than a lipo, no need for a regulator then.

[richard armstrong]

2 pack 2 rx set up running 16 ch, 1 control service to 1 RX port 12 in total?

this give me a small amount of RX redundancy, safety first in my eyes

the bigger the model the more redundancy

i am proberley over engineering it but better safe than sorry and piece of mind

[richard armstrong]

Use an A123 or LiFe battery rather than a lipo, no need for a regulator then.

rx pack lipos are now rated at a max 7.4 volts 2 cell

[richard armstrong]

the other thing i am pondering is weather to leave the kill switch as is on the side and manual

or to move internal and add a servo/rx to kill the engine

my gut feeling play it safe and move it internally????? pros and cons

[Rob Buckley]

Use a 2 cell LiFe, 6.6v nominal. Lower voltage so no need for a regulator.

What happens when the kill switch fails & turns the engine off?

Less to go wrong = safer.

[richard armstrong]

Use a 2 cell LiFe, 6.6v nominal. Lower voltage so no need for a regulator.

What happens when the kill switch fails & turns the engine off?

Less to go wrong = safer.

i take your point rob

might need to rethink this

[paul needham]

Richard, the thing to remember is 'KEEP IT SIMPLE', don't over complicate things.

[chris-berry]

Richard, what set-ups do you have in other models and how much do you fly them?

The reason I ask is that most people follow broadly the same format for most of their aircraft of a similar size and weight, so just do as you normally do.

What club are you in, as by taking it along for club mates to be able to see will probably glean better results than arms length discussion.

As Rob and Paul say, there will always be a weak point in any redundancy and it sometimes pays to keep as simple as possible, especially for what is, these days, a standard sized club model weighing about 13lbs and spanning about 80".

You may want to also try and find out what make the aircraft is. It looks to me to be ARTF in which case, somewhere,there will be signs of who made it, even if it's a QC stamp or mould marks on the horns etc. knowing who made it will help with research on correct c of g and flying characteristics, although hopefully, as it's a chipmunk it shouldn't be too bad!