Matronics Email Lists :: View topic - Nothing new then .......? At least the Jabiru can't boil ove

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

Nothing new then .......? At least the Jabiru can't boil ove

Matronics Email Lists Forum Index -> RotaxEngines-List

View previous topic :: View next topic

Author Message

ptag.dev(at)tiscali.co.uk
Guest

Posted: Sat Sep 01, 2007 10:36 am Post subject: Nothing new then .......? At least the Jabiru can't boil ove

Something fresh for you to “hew over ?”  

   

Hi! All.  

Rotax  advice please……..  

What’s best on a delayed departure to beat overheating assuming parked into wind?  

   

a) minimum idle with a course prop. setting  

or   

b) minimum idle with a fine prop. setting?  

Or   

c) medium RPM with a course prop setting?  

Or   

d) medium RPM with a fine prop. setting ?  

   

I managed a boil up today pleased I didn’t “go for it” because it happens in a flash.  

Bob H   

G-PTAG   

   

Robt.C.Harrison  

   

       [quote][b]

ptag.dev(at)tiscali.co.uk
Guest

Posted: Sat Sep 01, 2007 10:40 am Post subject: Nothing new then .......? At least the Jabiru can't boil ove

Something fresh for you to "chew over"?



Hi! All.

Rotax  advice please....

What's best on a delayed departure to beat overheating assuming parked

into wind?



a) minimum idle with a course prop. setting

or 

b) minimum idle with a fine prop. setting?

Or 

c) medium RPM with a course prop setting?

Or 

d) medium RPM with a fine prop. setting ?



I managed a boil up today pleased I didn't "go for it" because it

happens in a flash.

Bob H 

G-PTAG 



Robt.C.Harrison

Roger Lee

Joined: 10 Jan 2006
Posts: 1464
Location: Tucson, Az.

Posted: Sat Sep 01, 2007 11:51 am Post subject: Re: Nothing new then .......? At least the Jabiru can't boil

Hi Bob,



But Jabirus do over heat.

The answer I would pick form your mutiple choice is "D".

Medium rpm with a finer pitch. To course a pitch makes the engine work harder at low rpm which will builds heat faster. You want a finer pitch while at idle to let the engine work easier and with the medium rpm you may get a little more air flow.



Do you have a newer Roatx engine? If not you may want to check and see if you have the newer higher pressure radiator cap from a SB. If boiling over becomes an ongoing problem you may want to consider Evans NPG+ because its boiling point is about 100F higher than 50/50.

That said 50/50 will run about 40 F cooler after you are in the air with some better airflow.

_________________
Roger Lee
Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056

ptag.dev(at)tiscali.co.uk
Guest

Posted: Sat Sep 01, 2007 12:40 pm Post subject: Nothing new then .......? At least the Jabiru can't boil ove

Hi! Roger

Tks for the prompt reply.

Yes I had 600 hours of Jab overheating but now a little on tender hooks

after today's experience with the new 914.

I don't really want to use the Evans option since it is seemingly

inflammable.  Do you know what the increased poundage cap is? So I can

verify what I've been issued?

Regards

Bob H  G-PTAG



Ps appreciate your oil pressure uplift tip too.

--

ami(at)MCFADYEAN.FREESERV
Guest

Posted: Sat Sep 01, 2007 1:01 pm Post subject: Nothing new then .......? At least the Jabiru can't boil ove

I don't know about prop setting, but minimum idle  speed with a fixed pitch prop is best for keeping cool.

  

 Duncan McF.

 [quote]   ---

Roger Lee

Joined: 10 Jan 2006
Posts: 1464
Location: Tucson, Az.

Posted: Sat Sep 01, 2007 3:57 pm Post subject: Re: Nothing new then .......? At least the Jabiru can't boil

Hi Bob,



The new radiator cap part numbers is 922070 and it is 18 psi verses the old one at 13 psi.



I would try reducing engine load like the above post first.



The other thing is don't worry about the Evans. It is used in worse conditions than ours. It is also less flammable and of limited quanity than other items that will burn in your engine compartment. The Evans is the least of your worries. Just have to put Evans in perspective with everything else. There are other things in the engine compartment that burn easier, faster and hotter.



Firefighter and Hazmat Tech. 28 years.

_________________
Roger Lee
Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056

rparigor(at)suffolk.lib.n
Guest

Posted: Mon Sep 03, 2007 6:03 pm Post subject: Nothing new then .......? At least the Jabiru can't boil ove

Hi Bob



Here is some info on Evans as it pertains to my decision to use it on 914

Monowheel Europa:



http://contrails.free.fr/engine_burn_baby_burn_en.php



Evans will run a little hotter than 50/50, but don't think it will be 40F

(I have the general rise for Rotax powered Europas at hangar if you need).



According to John Hurst (was Europa USA in Lakeland) think it was 3 to

3500RPM and full course into wind yielded best cooling on ground for

Monowheel Europa. 



Option for extended ground operations, shoot some water from car

windshield wiper pump onto radiator, could always inject into motor to

help on climb out if not used on ground! I would use distilled water. Kim

Prout said someone by him on West coast did this with good success.



Supposedly this is good coating for 914 exhausts:

http://www.performancecoatings.com/

I am going to coat my 914 exhaust (to keep some heat out of cowl), if you

disassembled turbo you could do that too, but I am not, just going to wrap

with blanket from Aircraft Spruce. The same company sells a heat

dissipating coating I am going to have them do my 914 water radiator.



I forget but think you changed intake on your cowl, you could tuft it and

see what RPM and pitch with different wind angles yields best results. I

will mention it, but am pretty certain you have radiators well sealed so

any air is going through them instead of around.



I have no practical experience, but try pulling enricher and see if it

allows you to run cooler??



Ron P.

jetboy

Joined: 22 Jul 2006
Posts: 233

Posted: Tue Sep 04, 2007 12:59 am Post subject: Re: Nothing new then .......? At least the Jabiru can't boil

Bob I have no practical experience but if the problem continues would an electric radiator fan be suitable for grond running? should be lighter than carting around water to spray...



Hows the 914 installation working out? appreciate your comments vs. the previous setup



Ralph / CH701/ 2200a

_________________
Ralph - CH701 / 2200a

Roger Lee

Joined: 10 Jan 2006
Posts: 1464
Location: Tucson, Az.

Posted: Tue Sep 04, 2007 6:16 am Post subject: Re: Nothing new then .......? At least the Jabiru can't boil

Hi Ron,



I have run Evans in my last two 912's. It was fine until I switched it in my Flight Design CT. It has less cowl venting than my other plane. The Evans allowed me to see max temps. on warm days at takeoff and climb. I went back to 50/50 for some testing and it did indeed drop my CHT temps. 40F. Evans website and one other that I know of claim drops from 30-40F.

I like Evans, but it wasn't working out very well in my CT

Bob,



Aircraft Spruce does indeed have some muffler wrap that may cut some of the heat down. I used to use it on my helicopter.

I think better venting may help a little, but it is a ground idling issue. Maybe you can vent the heat out the top of the cowling.

I know the water spray will work as I have seen it, but think it is more of a bandaid and better solution would work.

As for the electric fan that may work if the fan is big enough to move enough air?



Have you tried different taxi techniques? Does this happen only in the summer months?

_________________
Roger Lee
Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056

ptag.dev(at)tiscali.co.uk
Guest

Posted: Tue Sep 04, 2007 12:12 pm Post subject: Nothing new then .......? At least the Jabiru can't boil ove

Hi! Ralf 

Thanks for the suggestion however I don't think an electric fan (subject

to there being sufficient room) would put more air through the rad tan a

prop.

There must be an optimum setting ...it's just finding it!

The 914 installation is complicated in comparison to the Jab. But

sophistication brings fuel savings and altitude power with exceptional

torque for take off too. Very different to get used to though.

Regards

Bob H  G-PTAG  



--

ami(at)MCFADYEAN.FREESERV
Guest

Posted: Tue Sep 04, 2007 12:25 pm Post subject: Nothing new then .......? At least the Jabiru can't boil ove

Bob,

Don't forget that any cooling difficulties will ease, if not disappear, 

after 20+ hours or so of running, as the engine eases-up



Rgds.,

Duncan mcf.

do not archive

---

Display posts from previous:

	Matronics Email Lists Forum Index -> RotaxEngines-List	All times are GMT - 8 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum