Norvel 1/2 A Texaco
03-04-2004, 05:23 PM
#1
Thread Starter
My Feedback: (2)
Join Date: Aug 2003
Location: Granada hills,
CA
Posts: 57
Likes: 0
Received 0 Likes
on
0 Posts
Norvel 1/2 A Texaco
Hi there,
Is anybody using the Norvel engines in 1/2A Texaco?
I intend to use a Big Mig for free flight 1/2 A Texaco and am getting about 4200 RPM on a 9-4 Taipan prop. Run time is quite long at this speed, as you might expect. Anybody else have any experience with these beasties? I was thinking of going to an electric prop as they might be easier on the crankshaft. Tried a Kyosho 9 inch but it was too much blade area and loaded down the motor.
I am not flying R/C where the rules require a Cox engine. Gave up on those as they are to finicky about cleanliness. These Russian engines just seem to laugh at dirt.
John in Kalifornea
Is anybody using the Norvel engines in 1/2A Texaco?
I intend to use a Big Mig for free flight 1/2 A Texaco and am getting about 4200 RPM on a 9-4 Taipan prop. Run time is quite long at this speed, as you might expect. Anybody else have any experience with these beasties? I was thinking of going to an electric prop as they might be easier on the crankshaft. Tried a Kyosho 9 inch but it was too much blade area and loaded down the motor.
I am not flying R/C where the rules require a Cox engine. Gave up on those as they are to finicky about cleanliness. These Russian engines just seem to laugh at dirt.
John in Kalifornea
03-04-2004, 05:41 PM
#2
My Feedback: (1)
Join Date: Mar 2003
Location: Mt. Pleasant,
OH
Posts: 1,249
Likes: 0
Received 0 Likes
on
0 Posts
RE: Norvel 1/2 A Texaco
I've been flying a much modified Gentle Lady with a Norvel Start Up .049 using an 8X5 wooden prop. Don't remember what it turns, but it's SLOW! I've had runs as long as 11 minutes on the tank that comes with the engine. The two things that seem to make it work are: 1) Lots of head gaskets, and 2) don't use an electric starter on it! The rod is some sort of alloy and I bent one by using a starter when it was slightly flooded. They seem to start pretty easily by hand with the larger props.
Some have voiced the opinion that the rotary valve engine isn't as well suited to "Texaco" type operation as the reedies since they're timed to run much faster while reed valve engines are timed for whatever they're running, but my experience with the very light airplane is that the extended run time outweighs the loss of efficiency from running 'bad' timing. It might work for you in FF Texaco, too.
Have you tried 'blueprinting' a Cox as per some of the instructions listed elsewhere in this forum? I've had much better luck with the little beasts since I did that.....longer, more consistent runs and lots more fun!
Some have voiced the opinion that the rotary valve engine isn't as well suited to "Texaco" type operation as the reedies since they're timed to run much faster while reed valve engines are timed for whatever they're running, but my experience with the very light airplane is that the extended run time outweighs the loss of efficiency from running 'bad' timing. It might work for you in FF Texaco, too.
Have you tried 'blueprinting' a Cox as per some of the instructions listed elsewhere in this forum? I've had much better luck with the little beasts since I did that.....longer, more consistent runs and lots more fun!
03-04-2004, 05:56 PM
#3
Thread Starter
My Feedback: (2)
Join Date: Aug 2003
Location: Granada hills,
CA
Posts: 57
Likes: 0
Received 0 Likes
on
0 Posts
RE: Norvel 1/2 A Texaco
No I haven't tried any tricks on the Cox engines recently. Twenty some years ago I tried the 1/2A pylon racing but found out I had neither the flying skills, eyesight or patience to be successful. I get enough frustration at my job without futzing around with those Cox engines. I'm using castor oil in the fuel and if you let the Cox engines sit too long they have to be taken apart and cleaned before they can be used.
John in Kalifornea
John in Kalifornea
03-04-2004, 06:00 PM
#4
Senior Member
Join Date: Jul 2003
Location: no city,
AL
Posts: 2,613
Likes: 0
Received 0 Likes
on
0 Posts
RE: Norvel 1/2 A Texaco
SAM rules specify a "Cox reed valve engine". This apples to both free flight and RC.
Interestingly both" Sam Speaks" and the MECCA publication have recently run articles in making the Cox reedies reliable. I have found by research, trial, and MUCH error that the vast majority of problems are caused by air leaks rather than dirt.
The author of the afore mentioned articles noted that many fliers gave up on 1/2 a Texaco due to problems with the engines. I quit .020 replica for the same reason. Mow , much to my surprise I have found that I can actually get the things to run!
Interestingly both" Sam Speaks" and the MECCA publication have recently run articles in making the Cox reedies reliable. I have found by research, trial, and MUCH error that the vast majority of problems are caused by air leaks rather than dirt.
The author of the afore mentioned articles noted that many fliers gave up on 1/2 a Texaco due to problems with the engines. I quit .020 replica for the same reason. Mow , much to my surprise I have found that I can actually get the things to run!
03-04-2004, 06:45 PM
#5
My Feedback: (1)
Join Date: Mar 2003
Location: Mt. Pleasant,
OH
Posts: 1,249
Likes: 0
Received 0 Likes
on
0 Posts
RE: Norvel 1/2 A Texaco
Jessiej, it sounds like we may have had the same experiences with the Cox reedies. I followed the instructions from the SAM article, the MECCA article, and the ones posted in this forum (at least those that fit within the Texaco rules) and have been very happy with the results. R/C 1/2 A Texaco might be even more popular if more people read those instructions!
One correction....the SAM rulebook says "Engines may be reed or rotary valve induction design." It doesn't specify a brand, either, but it does prohibit diesels. The fuel allotment is 1/2 oz, rather than the standard small reed valve tank we use in r/c Texaco.
One correction....the SAM rulebook says "Engines may be reed or rotary valve induction design." It doesn't specify a brand, either, but it does prohibit diesels. The fuel allotment is 1/2 oz, rather than the standard small reed valve tank we use in r/c Texaco.
03-05-2004, 06:04 AM
#6
RE: Norvel 1/2 A Texaco
These are only opinions:
Electric props...don't! I have not used them but read somewhere that they are not designed to handle wet engines. Remember that electrics provide smooth power where glow and diesel props must handle the shock of the engine firing every revolution.
Norvels with big props. Although I have not tried it, I would suggest playing with venturi restrictors to increase air velocity at lower RPMs. Might improve low RPM tuning and increase fuel economy.
Probably easier to learn to handle a Cox Texaco engine.
George
Electric props...don't! I have not used them but read somewhere that they are not designed to handle wet engines. Remember that electrics provide smooth power where glow and diesel props must handle the shock of the engine firing every revolution.
Norvels with big props. Although I have not tried it, I would suggest playing with venturi restrictors to increase air velocity at lower RPMs. Might improve low RPM tuning and increase fuel economy.
Probably easier to learn to handle a Cox Texaco engine.
George
03-05-2004, 01:15 PM
#7
Join Date: Oct 2002
Location: Chilliwack, BC, CANADA
Posts: 12,425
Likes: 0
Received 22 Likes
on
19 Posts
RE: Norvel 1/2 A Texaco
I believe that the SAM free flight Texaco event does not limit the engine type as the RC event does. Similarly I don't think they limit the props either. But you can check the rule book for these items.
As for running the Norvel on the big props like this I don't see anything wrong with it as long as you copy the same factors used with the Cox engines. Namely reduce the compression ratio to make setting the needle valve less critical and tune the firing point to the lower revs (sort of like retarding the spark advance). And the use of 5% fuel will extend your run time over higher nitro values. Nitro adds power but requires richer settings. Using lower nitro fuels lets you set the engine much leaner and extends the run time.
As for using electric props we had this discussion once before. You might try doing a search. But the gist of it was that as these RPMs there is nothing wrong with using the electric props IMHO. The ones to avoid would be the very light hubbed parkflyer type props.
I'm on the road as I post this but when I get home I'll post some pics of the highly modified Zinger props I did for use on my Cox Texaco models. The hubs in these cases are severley cut down to masses even smaller than the APC electric props. I've used the same props for over 10 years with no sign of failure. However I would not even consider using them in an application that took them much over 5000 rpms. Much the same as the electric props.
As for running the Norvel on the big props like this I don't see anything wrong with it as long as you copy the same factors used with the Cox engines. Namely reduce the compression ratio to make setting the needle valve less critical and tune the firing point to the lower revs (sort of like retarding the spark advance). And the use of 5% fuel will extend your run time over higher nitro values. Nitro adds power but requires richer settings. Using lower nitro fuels lets you set the engine much leaner and extends the run time.
As for using electric props we had this discussion once before. You might try doing a search. But the gist of it was that as these RPMs there is nothing wrong with using the electric props IMHO. The ones to avoid would be the very light hubbed parkflyer type props.
I'm on the road as I post this but when I get home I'll post some pics of the highly modified Zinger props I did for use on my Cox Texaco models. The hubs in these cases are severley cut down to masses even smaller than the APC electric props. I've used the same props for over 10 years with no sign of failure. However I would not even consider using them in an application that took them much over 5000 rpms. Much the same as the electric props.
