D&B 5.1 Twin Ignition Conversion
 

I purchased a D&B 5.1 twin and it has the older ignition that is built into the backplate of the engine. It is designed to operate on 4.8 volts and does not have shielded plug leads. I can upgrade to D&B's replacement 6 volt ignition for a whopping $180 that still does not have shielded plug wires but I am being told that is not an issue.
I can convert to a Rcexl unit for about $70. I have done many Rcexl conversions so it should be a "no brainer".

The D&B engines are top of the line but $180 for a new ignition?

Any other D&B 5.1 owners out there willing to offer up some advice?

Who has the better ignition? Rcexl (China ) or CH Ignition (USA )

Speedy, Get in touch with Adrien at http://www.ch-ignitions.com/ for the best advice, product and deal. Dan.

I also just purchased a used D & B 5.1. If the unshielded plug leads are not a problem, what's the reason for changing to a 6 volt ignition? 4.8 will deliver enough volts to fire the engine adequately.
I was more interested if there might be a weight loss with the newer style of ignition units.
Either way I think these are one nice engine for sure. I expect to fire mine up real soon.
Darrolair

I have two 5.1's and two 3.7's. The past four seasons I flew 1 o the 5.1 exclusively without radio problems with the exception of the telemetry. It would freeze after starting. I do plan to add shielding this winter and see what happens. Just one opinion here but I believe the two pickup ignition is far superior than the delay units in use today. I suspect this is due to initial cost, just like Mac and IBM, the best isn't always the most common.
I would believe that just adding the plug caps without the braid would solve my problem with telemetry but I did buy copper braiding from McMaster-Carr

I have some stainless braided coaxial cable and two cap kits from Rcexl. From what I understand you just pull the existing leads out and push the new ones in. I prefer 6V because I use a IBEC and prefer the higher voltage for my servos. I am not a "redundant dual everything" believer. You just need to be more attentive to your battery. I have been flying 30% for 5 years using a IBEC with absolutely no issues.

I plan to take the stock end off and slip the braiding back to the grommets leaving the stock resistor wire intact.

Speedy,
I now see your reasoning for the 6 volts.
So, are you planning to attach the braiding to the engine mounting bracket, or go internally and attach?
Can you post pics?
Interested,
Darrolair

Well....I have been talking with Ken at D&B and have decided to send the engine to him for a complete physical
including a full upper G.I. and colonoscopy. If it gets a clean bill of health I will run it as is. I can set the voltage
to the IBEC at 5.1 V and still run 6V to my servos. I will keep you all posted. Ken is a very knowledgeable guy
and I trust him since he did build engines for the late and great Miles Reed. What an awesome pilot and he could
not have performed as he did without an awesome reliable engine. I had the privilege to fly with Miles many times.
His D&B engines never missed a beat and no RF problems.

I also called Ken before purchasing this engine. These are Husqvarna pistons and cylinders. They are very reliable. I've operated many Husqvarna chainsaws and would only buy one other brand. Ken was very helpfull and knowledgeable. The previous owner had sent this engine in to Ken for a checkup.

Darrolair

I had one of these engines back in 2000. One of the sweetest running engines I have ever owned. At first I too had issues with RF and the little Briggs and Stratton type plug clips. My fix was a set of wires and caps off an old 3W ignition. Speedy, you are correct in that the old plug wires can be pulled out and new ones simply pushed in. Once you get the old ones out you will see a sharpened pin for the new wires to insert into. The new wires will most likely be a smaller dia. I just put a couple layers,of shrink tube on the ends to build them up and the a bead of Goop for added security. I did solder some wires to the braid and crimped on some lugs to attach to mounting bolts. Worked like a charm, that airplane had hundreds of flights with a pair of Hitec Supreme FM receivers.

My next question is... My D&B uses CM-6 plugs which are a non-resistor type plug so a resistor has to be placed where the lead meets the tip of the plug in the cap. Where is the resistor in the plug wire on the D&B lead wire to the plug? Agape Racing sells stainless braided plug wire material at $5.99/ft with 2 crimps and heat shrink.

Speedy, 3W and DA do not run resistors in their plug caps and run CM6 plugs as well. I had never seen this until the Chinese engines started showing up. However I do not think that adding the resistor is going to hurt anything. Once you source the wire you may want to just order up a couple DLE cap kits, they come with the resistors and instructions. The Reichmouth ( I know that is spelled wrong ) ignition that comes with the D&B engines is really well made and gave me no issues during hundreds of flights. In fact it was the most maintenance free engine I have ever owned.

I am just asking a question here but do you think the technology of the 20 year old Reichmuth (SP?) ignition is up to todays same standards as Rcexl and CH Ignition's standards?
Roy Sholl who is the owner of S&S machine says he can not compete with the price, dependability, and simplicity of Rcexl and CH. Roy has built his own brand of S&S ignitions for many years and he looked at this D&B 5.1 before I bought it and said it was in great shape mechanically but had no advise on the ignition since he was not familiar with it.

I suppose from a business standpoint I would think he may be right. Overall I think that the tech used in our current ignitions is a couple decades behind. IMO the only thing the new ignitions have over yours is the separate components used are manufactured with current materials and processes. I would like to see a smarter ignition. One that can be programmed via PC that would allow you to fine tune ignition curves as well as set the timing at start up and full throttle. That being said if I was to have that engine in my fleet I would leave well enough alone. I don't know if they did a custom curve or not but I do remember that the engines throttle response was one of the best I have ever seen. Changing the ignition with a slightly different curve could change that.

It's packed up in a nice box and going back to Ken at D&B on Monday for inspection. A buddy of mine has an all original 1947 Harley "Knucklehead" with the original cloth braided ignition wires and on a late summer night when the humidity is high he will start it up and you can actually see the plug wires arcing to the frame. It is a sight to behold and it runs like a champ!

Here's my 5.1 with new shielded wires and rear cover plate. This is in attempt to make the telemetry work, telemetry works after starting for a short time then locks up. I suspect it is noise(Hoping) from the ignition, will find out next season. I been flying this engine for three seasons and it still looks new inside and out.

Had not caught this a few weeks back but every DA ignition I have and the replacement caps have the resistor in place just like the Chinese Rcexl caps. I always thought that Rcexl just copied DA in this regard. The caps are almost identical to each other and clearly whoever made the dies and molds for the Chinese cap had the DA in their hands at the time.

That may have been an assumption on my part. The one 3W cap I took apart over a decade ago did not have a resistor. The DA cap is an exact copy of the 3W.

What's to say the DA and 3W caps are actually still made in the USA?

I just got my D&B 5.1 back from Ken Baker at Ridge Machine today. Ken went the extra-extra mile to get my engine
back to me in the absolute best condition. He tested the ignition for several hours looking for anomalies to which he
found none. Not one misfire in over 6 hours of ignition testing. He then completely went through the carb to make sure
it had all the upgrades and also replaced all gaskets. He then personally ran the engine and tuned it for peak performance.

Ken deserves a call-out here and some recognition for his knowledge, help, and professionalism.

Absolutely the best service and communication I have ever experienced in 45+ years of being in the hobby.

The late and great Miles Reed used these engines exclusively in his 85" Solution X bipes. That is plenty good enough for me.

When Miles flew......everyone watched....and learned how to do it right without all the gadgets and gizzmos.

Miles had "The Right Stuff"...he also had the right equipment. Maybe not the latest and greatest but it always
performed flawlessly and with authority.

Dennis Wann
Bryan, OH

Speedy,
So what you're saying is the original caps and wires are still in place.
I fired mine up the other day and it runs so smooth and throaty. Lots of pull for sure. Just had it bolted to my deck. Next summer it should get a work out.
Darrolair

YEP! Everything will remain as original. I believe that shielding the wires is not necessary.
What is necessary is good solid connections so no arcing is occurring. The 13" rule for
ignition to any closest radio devise which includes servos, switches, etc. Use a CORELESS
servo on the throttle. Lots of guys miss this one!

I forgot to mention in my other post that Ken even reworked my muffler stacks by removing
the old stacks and welding in new ones.

Speedy, let me be the first to ask. Why is using a coreless servo on the throttle of any unusual value? Dan.

The coreless servo reduces the possibility of harmonic feedback caused by vibration. Many years of pylon racing has taught me this.
A regular servo will generate electronic static from engine vibration or even control surface flutter. Don't believe it? Ask around the
local pylon racing gang. Vibration is a source of electronic static hell.

The 2.4 GHz radios have all but eliminated most of the RF interference issues but why not continue good practices even with
current new technology. If you are getting a anomaly then all these old practices can do nothing but help or be useful in the
process of elimination.

Rest assured, if I DO start getting RF problems I will shield the plug wires and caps. Maybe I am just lucky but I have not had a serious RF problem flying gas/ignition with the outdated FM PCM ( which I have discarded all ) or the new 2.4 Ghz systems.

Thanks Speedy. I never heard of that one but that’s what RCU is here for. Dan.