Pulse XT 60 CG

[gazzazh]

HI,

 

I just finished putting together my pulse xt 60, i have JR digital servos, Saito 100 GN and and evo 14x8 prop. i checked the CG on a great plane CG machine and found that the plane was nose heavy. Now this is only my third plane, i have flown a hangar 9 arrow which is a trainer, and then i moved to a Hangar 9 Cherokee low wing, been flying that for a while. and now i am getting into the pulse. My question is i read a lot on the internet that flying a nose heavy plane is much better than tail heavy.. So i was wondering can i make the test flight with a nose heavy and then readjust the CG ? I know this is a newbie question so my apologies

 

Cheers

 

 

 

[colin watson]

i would start with it balanced on the forward recomended cof g point this is a good starting point it can then be adjusted after the first few flights i test flew a model yesterday that even on it standard cof g was still tail heavy so adjusted it by adding weight to the nose so it flew how i like it. you can also experiment by moving the c of g rearward as your skills improve but beware as too much can have big implications on how your model behaves. what style of flying are you trying achieve as a sport or pattern flyer keep it neutrally ballanced,  for 3d style this usually requires a more rearward c of g.

check out threads regarding cg and checking by diving

happy flying

[gazzazh]

HI,

 

So dose that mean i can have a test flight with a nose heavy and then readjust after the first couple of flights ? 

 

Thanks

 

[colin watson]

not nose heavy if you have a cg range start with it balanced on its fwd point this will give you easy handling to test your cg start at a good height reduce throttle to tick over enter a dive approx 45 degs and see how your model reacts if it stays at 45degs it is ballanced for neutral handling. if it starts to pull up slightly you have tail heavy model if it gets a steeper dive you have a model which is nose heavy your pulse should be best flown neutrally balanced

[Biggles' Elder Brother - Moderator]

Hi Gazzazh,

 

you say "nose heavy" but you don't say how nose heavy! make a judgement you need to tell us what the CoG range should be (e.g. 21/2 to 3 inches behind the leading edge or what ever) and then where the actual CoG is - e.g. 21/4 inches behind the leading edge. Then we could give a better answer.

 

So specifying where the actual balance point is relatively to where it should be is what we need.

 

Generally speaking a plane with the CoG a LITTLE forward of the specified range (1/4 to 1/2 inch) i.e. a LITTLE nose heavy is OK, but not really recommended. The worst you'll get from that is a slightly nose down glide angle on approach and you might need a hefty bit of down elevator when inverted to get level flight. If the CoG is way forward - like an inch or more - then you'll have a ineffective elevator, and maybe will find it almost impossible to flair the plane for landing - result, usually a bust undercarriage

 

So, overall the very best advice, as Colin said, is get the balance point in the recommended range - preferably towards the front end of the range and don't settle for anything else.

 

BEB

[Biggles' Elder Brother - Moderator]

We cross posted Colin

 

BEB

[colin watson]

no problem we are both trying to help

[gazzazh]

Ok , i think i understand .. i will balance the plane as per your instructions... will get the plane in the balance point in the recommended range. This is the first plane i balance.. so i am just worried i make  a fatal mistake that would cause a crash on its test flight.... Thanks Colin, Thanks Biggles'Elder..... you have been a great help... 

 

Cheers

 

[Biggles' Elder Brother - Moderator]

Hi gazzazh, don't get too stressed out about it! As long as the balance point isn't a long way out nothing too awful is going to happen! The Pulse is a very well behaved plane. If the CoG is a bit back it will feel "lively" maybe even "twitchy" on the elevator. If its a bit forward it will feel "sluggish" on the elevator. You will also find that incorrect CoG tends to mean you have to keep retrimming as you move the throttle even relatively small amounts.

 

So, what's "a bit"? Well it varies really from plane to plane - some are more tolerant than others and its definitely more dangerous going backwards from the recommended range. The reason for this is that all the wing's lift can be thought of as acting through a single point called "the centre of pressure". If the CoG goes behind this point, then you really will have a "tiger by the tail"! But a quarter of an inch here or there, inside the recommended range, wont hurt - although, depending on your flying abilities, you may well "feel" the difference.

 

Enjoy the Pulse - you'll love it in the air.

 

BEB

[gazzazh]

Thanks a million Biggles'Elder .... You have been of great help... I am having the test flight this weekend... Wish Me Luck ... Cheers

 

[gazzazh]

I worked on the CG, had to place the battery a little back .. got a perfect CG... Made my test flight today.... WOW.. .all i had o do was 1 trim left... and thats its...This is an amazing plane.. flies really nice,,, and its lands beutifully... 

 

I wanted to thank you all, would not have done the CG without you Guys... Thanks a million

 

Cheers

 

[Biggles' Elder Brother - Moderator]

Great to hear it went well, have fun - it certianly is a great plane (Hanger 9 kits aren't cheap, but maybe you get what you pay for!)

 

Happy landings

 

BEB