HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Jan 18, 2013, 12:15 PM
Registered User
DarZeelon's Avatar
Israel, Ramat HaSharon
Joined Nov 2003
1,165 Posts
Quote:
Originally Posted by AeroFinn View Post
And I bet 0% nitro / 10% oil fuel blend gives more power than running on gas (this is, however, my assumption. I don't have any data to prove this).
Finn,


You've got plenty of data to prove it on the web.

Although methanol has roughly 55% of the specific energy of gasoline/petrol, its stoichiometric ratio allows you to oxidise about 2.4 times the methanol, with the same amount of oxygen.

So, under ideal conditions, you should be able to get ~24% more HP from methanol, while using it 240% as fast.
Methanol also has a higher resistance to detonation than gasoline, so you can run a significantly higher compression-ratio and get even more power.


Sr., it is just terminology... To me retarding the spark sound like it happens after TDC. But it can also mean less advance.
DarZeelon is offline Find More Posts by DarZeelon
Reply With Quote
Sign up now
to remove ads between posts
Old Jan 18, 2013, 08:51 PM
I HATE GLOW PLUGS!
SrTelemaster's Avatar
United States, NY, St Lawrence
Joined Feb 2012
1,295 Posts
Quote:
Originally Posted by DarZeelon View Post



So, under ideal conditions, you should be able to get ~24% more HP from methanol, while using it 240% as fast.
Methanol also has a higher resistance to detonation than gasoline, so you can run a significantly higher compression-ratio and get even more power..

I have found that a STOCK Saito engine converted to CDI burning glow fuel W/15% nitro 17% oil yields about 22% more power than Saito's claimed HP output for similar sized engines.

It would not surprise me if 0% nitro 10% oil would yield similar results.

That falls pretty darned close to the 24% estimation above.

It is reasonable to expect that a methanol/CDI engine will produce the same power output as a gasoline burning counterpart W/a lower throttle setting. (for the CDI/methanol engine) This fact would further mitigate the cost penalty for methanol operation when a given level of flight performance is acheived for both scenerios.

This also gives the CDI/methanol combination more apeal to many.


Quote:
Originally Posted by DarZeelon View Post


Sr., it is just terminology... To me retarding the spark sound like it happens after TDC. But it can also mean less advance.
Exactly!
SrTelemaster is offline Find More Posts by SrTelemaster
Last edited by SrTelemaster; Jan 18, 2013 at 08:57 PM.
Reply With Quote
Old Jan 20, 2013, 02:01 AM
Registered User
Joined Feb 2007
29 Posts
Quote:
Originally Posted by SrTelemaster View Post
The spark curve is more of a retard than advance. When you set the system up you are setting the initial spark @ full advance. With methanol, that's going to be about 34-36* BTDC (you will make small adjustemnts after starting to find the minimum advance that gives maximum RPM)

I read how some are trying to static time by the magnet/hall sensor position relationship. That seems like a haphazard way. By removing the plug from the cylinder & installing it in the McDaniels plug socket, you can see/hear the spark event. No need to ground the plug as the socket/lead are grounded to the module via the braided SS shiled on the lead. I use the spark plug W/a degree wheel & slowly turn the engine through the spark event, carefully noting the reading on the degree wheel as I see/ear the spark.


Back to the timing curve. W/the spark set @ the full advance setting, the module will retard the spark 24* @ low RPM settings. (about 400 RPM & slightly above) This allows starting W/O kickback & good idle. As the RPM increase, the module backs off the retard until it reaches the initial setting @ 4000+ RPM.

If you haven't seen my thread about setting up C&H CDI here is the link.

http://www.rcgroups.com/forums/showthread.php?t=1774802
SrTele
What where the differences in the system characteristics of Rcexl and CH ignitions? I think I'v seen a post where you had this commented but could not find it..
AeroFinn is offline Find More Posts by AeroFinn
Reply With Quote
Old Jan 20, 2013, 09:12 AM
I HATE GLOW PLUGS!
SrTelemaster's Avatar
United States, NY, St Lawrence
Joined Feb 2012
1,295 Posts
Quote:
Originally Posted by AeroFinn View Post
SrTele
What where the differences in the system characteristics of Rcexl and CH ignitions? I think I'v seen a post where you had this commented but could not find it..
The RCEXEL is a copy of the old C&H modules from way back. The newer C&H modules are lighter, more compact & repairable. The new C&H modules can be had in differing spark curves for specific engine requirement.


The BIG differance is the way that the hall sensor & trigger magnet are installed.

1. C&H sends you an aluminum ring that carries the trigger magnet. It is slipped over the prop hub & secured W/set screws. It is infinaetly adjustable & does not require removal of the prop hub. It makes adjustemnt & tuning very easy to accomplish.


RCEXEL sends you a magnet. It is up to you to remove the prop hub, drill it & press in the magnet. You must then instal the prop hub @ nearly the exact position needed for proper ignition timing! Good luck W/that. Then, many have experienced a shift in the prop hub on the initial start up. After the initial start, the prop hub will remain secure, but now you will have to go back & re-time the spark if there wqas a shift on the initial start. There may or may not be enough adjustment as the adjustment provision in the hall sensor clip is limited as will be detailed below.

2. The hall sensor mount for the C&H systems for Saito engines mounts securely to the cam housing. Just remove the 2 front screws & install the hall sensor mount. Timing is not adjusted via the hall sensor on the C&H systems.


RCEXEL systems require that you drill & tap the case to mount the hall sensor clip. Furthermore, the clip has limited adjustment so proper orientation of the prop hub is paramount to being able to properly time the ignition. The clip on te RCEXEL system is also fragile (plastic) compared to the C&H CNC aluminum mount.

The C&H syatem is pretty much "plug & play" whereas the "one size fits all" RCEXEL has to be "tailored" to each application.
SrTelemaster is offline Find More Posts by SrTelemaster
Reply With Quote
Old Jan 20, 2013, 02:43 PM
Registered User
Joined Feb 2007
29 Posts
Quote:
Originally Posted by SrTelemaster View Post
The RCEXEL is a copy of the old C&H modules from way back. The newer C&H modules are lighter, more compact & repairable. The new C&H modules can be had in differing spark curves for specific engine requirement.


The BIG differance is the way that the hall sensor & trigger magnet are installed.

1. C&H sends you an aluminum ring that carries the trigger magnet. It is slipped over the prop hub & secured W/set screws. It is infinaetly adjustable & does not require removal of the prop hub. It makes adjustemnt & tuning very easy to accomplish.


RCEXEL sends you a magnet. It is up to you to remove the prop hub, drill it & press in the magnet. You must then instal the prop hub @ nearly the exact position needed for proper ignition timing! Good luck W/that. Then, many have experienced a shift in the prop hub on the initial start up. After the initial start, the prop hub will remain secure, but now you will have to go back & re-time the spark if there wqas a shift on the initial start. There may or may not be enough adjustment as the adjustment provision in the hall sensor clip is limited as will be detailed below.

2. The hall sensor mount for the C&H systems for Saito engines mounts securely to the cam housing. Just remove the 2 front screws & install the hall sensor mount. Timing is not adjusted via the hall sensor on the C&H systems.


RCEXEL systems require that you drill & tap the case to mount the hall sensor clip. Furthermore, the clip has limited adjustment so proper orientation of the prop hub is paramount to being able to properly time the ignition. The clip on te RCEXEL system is also fragile (plastic) compared to the C&H CNC aluminum mount.

The C&H syatem is pretty much "plug & play" whereas the "one size fits all" RCEXEL has to be "tailored" to each application.
SrTele, great synthesis and highly valued! So basically you need to have acces to a lathe & associated techical skills to mount the Rcexl system properly. That is, make an adjustable magnet ring at least. (Well, there might be industrial type double-split shaft collars available that one could use to create an adjustable magnet ring but things get fussy..)

As the new CH modules can be had in different spark curves for different engine requirements; does this mean one should describe carefully the engine type and fuel type that's going to be used etc. upon placing an order for a module? (I tried to find info on this on the CH-Ignitions.com but I didn't find any)
Thanks a lot again.
AeroFinn is offline Find More Posts by AeroFinn
Reply With Quote
Old Jan 20, 2013, 03:32 PM
I HATE GLOW PLUGS!
SrTelemaster's Avatar
United States, NY, St Lawrence
Joined Feb 2012
1,295 Posts
Quote:
Originally Posted by AeroFinn View Post
SrTele, great synthesis and highly valued! So basically you need to have acces to a lathe & associated techical skills to mount the Rcexl system properly. That is, make an adjustable magnet ring at least. (Well, there might be industrial type double-split shaft collars available that one could use to create an adjustable magnet ring but things get fussy..)

As the new CH modules can be had in different spark curves for different engine requirements; does this mean one should describe carefully the engine type and fuel type that's going to be used etc. upon placing an order for a module? (I tried to find info on this on the CH-Ignitions.com but I didn't find any)
Thanks a lot again.
For the Saito 4-stroke Adrian will supply an appropriate spark curve.

Adrian can fabricate a module W/virtually any spark paramaters but in our case the stadard vanilla spark curve works just fine.

As far as technical skills needed to instal the C&H system? If you can use an allen wrench & have the 3rd grade expertise W/scissors & paste to glue the degree wheel that is printed on the instruction onto a suitable backing, you are most of the way there.

No drills, no taps needed.
SrTelemaster is offline Find More Posts by SrTelemaster
Reply With Quote
Old Jan 24, 2013, 10:47 AM
Registered User
Joined Feb 2007
29 Posts
Quote:
Originally Posted by SrTelemaster View Post
For the Saito 4-stroke Adrian will supply an appropriate spark curve.

Adrian can fabricate a module W/virtually any spark paramaters but in our case the stadard vanilla spark curve works just fine.

As far as technical skills needed to instal the C&H system? If you can use an allen wrench & have the 3rd grade expertise W/scissors & paste to glue the degree wheel that is printed on the instruction onto a suitable backing, you are most of the way there.

No drills, no taps needed.
Ok. I Placed an order on a CDI for FA-125a glow with installation kit from Adrian. Thanks again SrTele for great help and guidance! I just realized that the operating voltage can be selected. Is the 4,8volt recommendable? I guess that would suit for 1 cell LiPo, too if weight is an issue. The CH-ignitions internet site recommends 4,8v 1200mAh. One cell LiPo would be super light, of course:

http://www.hobbyking.com/hobbyking/s...und_Lipo_.html

anyways, I'm looking forward to getting my shipment from adrian. I guess I need to buy a kill-switch too and maybe some spare spark plugs but I didn't want to buy them at the same shipment as I try to keep the value of the shipment as low as possible and thus avoid all kinds of VATs and customs fees. Let's see if I'm lucky or not..
AeroFinn is offline Find More Posts by AeroFinn
Reply With Quote
Old Jan 24, 2013, 10:51 AM
I HATE GLOW PLUGS!
SrTelemaster's Avatar
United States, NY, St Lawrence
Joined Feb 2012
1,295 Posts
Quote:
Originally Posted by AeroFinn View Post
Ok. I Placed an order on a CDI for FA-125a glow with installation kit from Adrian. Thanks again SrTele for great help and guidance! I just realized that the operating voltage can be selected. Is the 4,8volt recommendable? I guess that would suit for 1 cell LiPo, too if weight is an issue. The CH-ignitions internet site recommends 4,8v 1200mAh. One cell LiPo would be super light, of course:

http://www.hobbyking.com/hobbyking/s...und_Lipo_.html

anyways, I'm looking forward to getting my shipment from adrian. I guess I need to buy a kill-switch too and maybe some spare spark plugs but I didn't want to buy them at the same shipment as I try to keep the value of the shipment as low as possible and thus avoid all kinds of VATs and customs fees. Let's see if I'm lucky or not..
I've have always used 4.8v packs.
SrTelemaster is offline Find More Posts by SrTelemaster
Reply With Quote
Old Jan 24, 2013, 11:14 AM
Registered User
Joined Feb 2007
29 Posts
Quote:
Originally Posted by SrTelemaster View Post
I've have always used 4.8v packs.
ok thanks

So i'll ask Adrian to make the module for 4,8v

The one cell Lipo was mentioned here:

http://ch-ignitions.com/index.php?id...controller=cms
AeroFinn is offline Find More Posts by AeroFinn
Reply With Quote
Old Jan 24, 2013, 11:18 AM
Registered User
DarZeelon's Avatar
Israel, Ramat HaSharon
Joined Nov 2003
1,165 Posts
I believe most today would want to use a two-cell LiFePO4 pack, connected directly for power.
I.e. no IBEC is used (which is another potential point of failure) and its nominal voltage 6.6V.

Can the CH systems use such voltage (7.2V fully charged)?

The site specifically shows voltages up to 7.2V, were tested by CH and worked; but still warns that using over 6V is at the user's own risk...

Could Adrian make the changes needed, so this warning will not be required?


After all, even airborne R/C receivers and servos are now fast becoming 'high-voltage', rated for up to 8.4V.
DarZeelon is offline Find More Posts by DarZeelon
Reply With Quote
Old Jan 24, 2013, 11:30 AM
I HATE GLOW PLUGS!
SrTelemaster's Avatar
United States, NY, St Lawrence
Joined Feb 2012
1,295 Posts
Quote:
Originally Posted by DarZeelon View Post
I believe most today would want to use a two-cell LiFePO4 pack, connected directly for power.
I.e. no IBEC is used (which is another potential point of failure) and its nominal voltage 6.6V.

Can the CH systems use such voltage (7.2V fully charged)?

The site specifically shows voltages up to 7.2V, were tested by CH and worked; but still warns that using over 6V is at the user's own risk...

Could Adrian make the changes needed, so this warning will not be required?


After all, even airborne R/C receivers and servos are now fast becoming 'high-voltage', rated for up to 8.4V.
Each individual module comes marked for voltage input.

They can be ordered for whatever voltage you specify.

The last module I got from them had check boxes for 4.8v, 6v, 7.4v & 12v.
SrTelemaster is offline Find More Posts by SrTelemaster
Last edited by SrTelemaster; Jan 24, 2013 at 01:46 PM.
Reply With Quote
Old Jan 24, 2013, 01:06 PM
Registered User
Joined Feb 2007
29 Posts
Quote:
Originally Posted by SrTelemaster View Post
Each individual maodule come smarked for voltage input.

They can be ordered for whatever voltage you specify.

The last module I got from them had check boxes for 4.8v, 6v, 7.4v & 12v.
Well, I just got e-mail from Adrian. He says the best system operating voltage today is 6-6,6v and one cell LiPo isn't enough. So he made my module to 6-6,6v. I guess today's standard is 2 cell LiFe 6,6

here's one that weighs 84 grams
http://www.hobbyking.com/hobbyking/s...ver_Pack_.html

and another a bit smaller and lighter

http://www.hobbyking.com/hobbyking/s...ver_Pack_.html
AeroFinn is offline Find More Posts by AeroFinn
Reply With Quote
Old Jan 24, 2013, 01:58 PM
I HATE GLOW PLUGS!
SrTelemaster's Avatar
United States, NY, St Lawrence
Joined Feb 2012
1,295 Posts
Quote:
Originally Posted by AeroFinn View Post
Well, I just got e-mail from Adrian. He says the best system operating voltage today is 6-6,6v and one cell LiPo isn't enough. So he made my module to 6-6,6v. I guess today's standard is 2 cell LiFe 6,6

here's one that weighs 84 grams
http://www.hobbyking.com/hobbyking/s...ver_Pack_.html

and another a bit smaller and lighter

http://www.hobbyking.com/hobbyking/s...ver_Pack_.html
Why would you need a high discharge capacity battery pack.?

I have run single cylinder C&H systems W/650ma & smaller NiCd/NiMh packs.

I think the draw is .8a.

The smaller pack will be more than adequate.
SrTelemaster is offline Find More Posts by SrTelemaster
Reply With Quote
Old Jan 24, 2013, 02:02 PM
Registered User
Joined Feb 2007
29 Posts
Quote:
Originally Posted by SrTelemaster View Post
Why do you need a high discharge capacity battery pack.?

I have run single cylinder C&H systems W/650ma & smaller NiCd/NiMh packs.

I think the draw is .8a.
Well, to be honest I just picked up the two just by their capacity 1000+ mAh as recommended in CH-ignitions.com site

Andrian said the best performance (?) today would the 6-6,6v system so therefore I thought Life might be lighter than NiMh
AeroFinn is offline Find More Posts by AeroFinn
Reply With Quote
Old Jan 24, 2013, 04:21 PM
I HATE GLOW PLUGS!
SrTelemaster's Avatar
United States, NY, St Lawrence
Joined Feb 2012
1,295 Posts
Quote:
Originally Posted by AeroFinn View Post
Well, to be honest I just picked up the two just by their capacity 1000+ mAh as recommended in CH-ignitions.com site

Andrian said the best performance (?) today would the 6-6,6v system so therefore I thought Life might be lighter than NiMh
The heavy battery is 1450Ma & is spec'ed W/a high discharge rate.

Yes the 1000+ Ma is good for less frequent charging, but the amp draw is not high so no need for hig dischage rate batteries.
SrTelemaster is offline Find More Posts by SrTelemaster
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
For Sale new Saito FG-20 airtimeallen Aircraft - Fuel - Engines and Accessories (FS/W) 2 Jun 18, 2014 12:58 PM
Discussion Saito FG-21 gasser skypup Engines 64 Apr 01, 2014 11:50 PM
For Sale Saito FG-20 airtimeallen Aircraft - Fuel - Engines and Accessories (FS/W) 0 Jun 30, 2012 01:47 PM
Off Site New Saito FG-20 in the Box JetA320 Aircraft - Fuel - Engines and Accessories (FS/W) 0 Jun 12, 2012 04:48 PM
Discussion Saito FG 20 discontinued, Hello FG 21 Ayeager Engines 1 Apr 27, 2012 11:03 PM