tuning hatori 970

[ferry]

hello heli people
i have a tune problem.
i have a nt , with sz91 , a henseleit [mp91] krummer , and a hatori970 .
i found out that there are 2 different 970 pipes in production.
they have different distances to the first baffle [prallplatte?]
mine is 25 cm.

the weird thing is , jan h advices in the mp91 manual , to put on the header from him , and a hatori 970 . inbetween the krummer and 970 he advises 3mm gap.
i mailed jan , and asked him what length he advices on my nt , and he says ;try 43 cm

the way jan says in the manual , the length from first flange to baffle or prallplatte , is only 38 cm.
jan's krummer is only 13 cm . i have a 10 cm vario teflon tube in between , and with that i get it to be max 43 cm .
so , how can it be that on the mp91 it is best to have 38 cm , while the same motor goes on the nt , and everybody is flying that on 41 or more ?

also , i fly 10 or 15 % nitro , does that means the length has to be longer ?
and what symptoms you get if the pipe is too short ?

if you have a hatori 970 running good , please tell me your tune tips !
antwort in deutsch ist kein problem!!
danke , gruss ferry

[Andy2211]

Hi ferry,
your motor will heat up extremely if your pipe's distance is too short.
If you use more nitro you have to eke your distance of the pipe.

If you want to get the best distance between your pipe and the zylinder head you have to play with it.

regards,
Andy

[ferry]

danke andy.
eeh , i dont get ; 'eke your distance of the pipe'
what you mean , shorter with more nitro or longer?
so , too short is ; motor running hot
and how about too long ? cold motor ? not getting to the headspeed of 1900 due to bogging ?

i flew a long time with 38 cm and that was only good in mid range.
now i experiment with it , and i made it about 42 cm .
leushy adviced me to try 46 cm with my fuel , but that is not possible with the teflon pipe aswell as my balance.

danke und gruss , ferry

[Andy2211]

Hi,
you need a longer distance with more nitro.

I don't know what happens if your distance is too long. I only noticed on my NT that the enginge was running to hot with too short distance.

regards,
Andy