Purchased a Byron Hellcat that had sat in its orginal kit boxes for 5-6 years, including a Precision Eagle 4.2 with CH Electronic Ignition and Byron 3-blade flyng prop.

I'm getting 3400 RPM tops out of the engine, but have not flown it yet, as I have no documentation on what RPM the engine should be putting out with this prop and have gotten widely differing estimates from various sources.

The engine is running fine from idle through transitions to high end, and over extended run times. It also starts very well (couple flips of the prop w/choke closed, igntion off, followed by one or two flips of the prop w/choke open, igntion on). It runs great, except that it 'seems' like it should have higher RPM. Received documentation was complete (meaning nothing was missing from the kit), but was not helpful on expected performance info.

Perhaps its fine, and its just my ignorance of engines and props in this size range that is giving me grief. Also, I'm using digital tach with a 3-blade setting to measure RPM.

Would appreciate feedback from anyone with actual flying experience with Precision Eagle 4.2/Byron Prop combinations.

Since Iron Bay now owns Byron, perhaps there are 'Iron Bay Pilots' out there now with applicable experience.

Have contacted some of the obvious sources that I should go to for feedback - and this is where the wide range in results is coming from (3000 RPM, 3400 RPM, 5400 RPM, 7000 RPM - the latter is probably for a much smaller, two bladed prop, as its a maximum value I found on a Precision Eagle web page; the 3000 is from the same page).

So if there is someone out there that has run this combo, please let me know what RPM you're getting.

Thank you.

They Byron prop system is a gear drive reduction right?
Figure our the reduction ratio by counting the number of teeth on each of the gears and dividing the numbers into each other. Take your measured prop rpm and multiply by this ratio - this tells you the actual engine rpm. If it's in the range of 6,000-8,000 then your engine is likely turning in the desired power range for this size engine.

Byron made hub adapters for the larger engines...The two skinny polyflex belts won't transmit the power of a large engine..Iron Bay would be the best bet for info.................Best prop would be a 24-8 Menz or Mejzlik two blade for performance, leaving the multi blade for display.....

No, a gear reduction drive is not utilized - this is a direct drive setup.

No gear reduction, no belts. However, I believe I will get a prop adapter so that I can swing a two blade prop. This would at least let me get some comparative data on both RPM and thrust.

Thank you.

Can't believe a year has gone by. Doing everything but flying and finishing my aircraft.

Have just started the finishing of this Hellcat/Precision Eagle setup, again. Have uncovered supporting documentation regarding the 2-blade conversion, and info regarding proper sizing of 3-blade equivalent props.

The Byron prop is oversized, overweighted given the power of the 4.2 PE - not surprising.

Contacted Iron Bay a couple days ago - they're working on drawings for the 2-blade prop adapter, and have none in stock. Hoping someone might have one left over from - either one not being use, or perhaps the aircraft no longer exists due to some unfortunate incident.

Else, I expect I'll have to generate my own drawing and find a machinest.

If you are anyone else has a suggestion, let me know. Precision Eagle is not a possible source, I'm told, as they no longer make the 4.2, having switched to a 4.6 with no common components from the 4.2. Will also check any "Sachs" sites.

Try C&H ignitions or maybe RC Ignition. I have purchased a couple of adapters from C&H in the past for 3.2 sachs based motors. I'll bet he can fix you up with what you need.

Keep us up to date on your progress with this engine. I was going to post a question about whether anyone had used this engine, so I'm interested to hear how you make out.

Thanks

Kerry

Also forgot to add, I'm interested in the Iron Bay (Byron) Hellcat. Maybe you can post your experiences with this kit over on the Warbird forum

Kerry

Will do, when I get some experience. Not likely this year - snow is coming and looks like sorting the prop adapter issue is going to take some time.

I've spoken with a Byron Originals employee and a RC warbird custom supplier (he builds finished aircraft for others and makes a living, I'm told - nice life) in San Diego. Both said the Hellcat was the best/easiest flying of the Byron kits - which also lines up with full-scale comparisons.

This was my first big, first glass fuse, first poly-resin glassing of wings/stab, first spraying with an airgun, first use of latex paint, kit. I wish I had not had so many 'firsts' with this build - its probably not a kit I should have taken on, yet. With better experience, I could have built it lighter, espcially in the all the areas of the CG!

But, it is certainly doable - I've had the plane out to the field and get alot of great comments and people taking pictures. The most often heard comment is "When are you going to fly it?" Everybody wants to be around with this happens.

With so many firsts on this plane, the flying of it will NOT be performed first by me. Have had many recommendations and will follow the full-scale process of letting someone skilled on this type fly it first and then train me.

If you do get the kit and have any questions, let me know. I have some 'lessons learned' and a few things I did which I think were kind of neat, like blind mounts for the cowling and canopy slide rails. For the most part, I can say that I enjoyed building this kit. There were a few kit quality issues, but if I had checked things out a bit farther before gluing/sheeting, I would have saved quite a bit of rework. Also, I originally used Super Coverite on the wings/stab and this turned into a disaster. If you've ever used this material in the past, you'll note the new stuff by the same name is quite different - the new stuff doesn't like a dark paint job and a hot sun!

My kit was a Byron Original, left in someone's basement for several years. I'm not familiar with Iron Bay's packing of the kit, so I can't say if they've made any improvements or not. If you can get the kit with the 4.6 Precision Eagle engine - go for it. I understand everything is a bit bigger on it, so I assume the weight will be a bit higher too (this may be a bad assumption, I know). The increased power may be enough to really turn the scale Byron prop. And, if there is a bit more weight with the bigger engine, you'll need less dead weight when balancing that tail that seem to stretch out there forever. I'm told that the 4.6 is more efficient and cleaner running - hope so as the 4.2 seems to spit alot of unburned fuel OUT of the carbuerator, even when running lean.

One update I didn't make is that I'm now getting 5000 RPM out of the engine with the Byron 3-blade prop. Still lower than what I want, but now in the 5000-5600 range spec'd for the combination.

Mixture and break-in time seem to have had little impact. Biggest change came with the position adjustment of the ignition timing sensor (using full electronic CH ignition, not the throttle coupled advance setup).

Talking with CH, this change in position setting may likely have been required do to altitude differences and/or plastic creep - the kit/engine did sit unbuilt and unused in box for several years before I obtained them.

Nice plane. I would just go to a smaller propeller. I would recommend that you run the engine around 7000-7500 rpm.

DaleCS,

I have a Byron P-40 with the Predision Eagle 4.3, Purr Pow'r & 3 blade sysem that I am finishing up. Everyone that I have talked to about this setup states that the P-40 will fly very scale-like with the 3 blade prop but the performance will be increased if a 2 blade sysem is used. Since I do not want to take a chance on breaking the 3 blade on test flights, I am going to get a 2 blade adapter and use wood props until I get used to flying the P-40. If these adapters are not available from Iron Bay, I have a fellow club member that is a machinist.

Did the latex paint work out pretty good? Since I do not have any experience with latex, I am looking for any tips & pointers...

Smooth Landings,
Jake

Most of the time CH Electronics has the prop hub and single bolt adapter for use i\on these engines. These alow use of normal 2 bld props with out any drilling.

I've heard the same things about the scale prop and scale performance - and I also want the higher power during initial flights and training. Better to find out you have more than you need that not enough.

The latex paint turned out pretty well. I had some help from someone in the Washington DC area - lost his address and all files on the subject when my hard disk died. Didn't have my email traffic backed up, either. So hopefully, he'll be on RCU and pick up on the thread. Would like to thank him.

I used Bear exterior latex from Home depot, a bit of Floetrol and windshield wiper fluid - both to improve flow/performance out of the gun. I don't have enough experience to say the windshield wiper fluid made a difference - I just followed recommendations from others that had a barn full of aircraft painted this way.

I would caution you on two things:

- If you use the windshield wiper fluid (I used an amount in accordance with the Floetrol recommendations), be careful where you buy it from - some auto parts stores will sell this material in concentrated form, even when its labeled 'not for retail sale.' I found this out the hard way, as the jub wasn't clearly labeled.

- It takes several weeks for latex to cure to the point where it won't stick to itself. It will cure tack free and handleable rather quickly, 'stick-to-itself free' is another matter. If you want to assemble your plane before everything is fully cured, cut up some wax paper to put between any joints where the latex meets (e.g. between inboard and outboard wing panels). If you don't do this and assemble the plane leaving it overnight, you may find paint being pulled off in these joint areas when you diassemble the panels.

- Also, I still don't know exactly how long one must wait until latex is unaffected by raw fuel. Several weeks after painting, I installed my engine and started it up. I didn't wipe the 'spit' from the carbuerator off right away and found that I needed to retouch a few areas where the paint started to soften. I don't wait any longer, I clean up immediately, and everything is fine. Its been a year, and the latex may be cured to the point where I don't have to worry, but I'd rather test on something else. Also, the overly long cure times may have been related to that concentrated windshield washer solvent.

No one at the club can tell this is a latex job - it looks fine. By using latex, I also had the benefit of not sending my wife into fits with headaches. And even though the smell is something one can live with while painting, always use a respirator.

Would I use latex again? Probably, if I were to paint the aircraft myself. The benefits working with latex are worth the learning curve I went through. But I have friend at our church that owns an auto paint shop - I think I'll call him next time and try an automotive finish. He's a much better painter than me and already has the spray boxes and ventilation needed for using such materials.

Regarding the matching of military spec colors, I found the local hobby shop to be a great source - they've got all those little bottles and spray cans of paint for military scale plastic models. Many of those bottles and cans are labeled with the same military paint spec numbers. Buy a bit, spread some on a white card and take it to a latex supplier with one of those paint matching computer systems.

Good luck.

Hi DaleCS,

Thanks for the painting tips! I also have a friend that is a body man at a local Chevy dealership and he offered to have a painter friend of his shoot my P-40, but I think I would like to do it myself. I am hoping to fly this P-40 at the Gunsmoke Scale Masters Qualifier this February in the Phoenix area, so need to get going!!!

Here is a photo take from a Revell box of the color scheme that I want to do. Then Lt. Sidney Woods from Somerton, AZ flew a P-40 like this one in the Pacific during WWII.

Sorry for the poor quality of the photo...

Thank you - contacted CH and I know have the hub/single bolt adapter on its way. Should arrive next week of 20Oct2003.

Thank you - contacted CH and I know have the hub/single bolt adapter on its way. Should arrive next week of 20Oct2003.

How much does your engine weigh with muffler?

I don't know and its pretty difficult to get the thing out to weigh it. I need to put in an access hole thru the fuse and get a really long T-handle wrench to get at the socket head bolt on the rear mount.

Haven't found a retailer with a long enough tool, yet, so I've hesitated to open holes in the fuse if they're going to be no-value added.

How important is the answer? I can pull the engine if you really need the data.

Geistware,

Here are the specs from my PurrPow'r manual for the Precision Eagle 4.2 with the three blade prop:

Static RPM 5000-5400
Static Thrust 23-26 lbs
Prop 23 1/2"
Weight 7 lbs 4oz

Hope this helps...

One update on the latex:

I finally got my prop adapter and started swinging the 2 blade, prop. I'm getting quite a bit of raw fuel spitting from my carb (I don't know that this is normal - never had such an experience with my chainsaw, line trimmer, etc., but those had air filter systems on them). I'm finding that the raw fuel oil mixture will soften the latex, even after the latex has set for over a year.

Keep the raw fuel/oil off your latex paint job. If it gets on your paint, wipe it off gently, first spraying it with some Windex or similar product, then lightly touching with a paper towel or other disposable rag (I set such rags off to the side for a week or so before disposing of them, to let the gas evaporate off of them).

If you follow this method, the latex will harden again. If you don't, and press/wipe hard, you'll peel the paint off!

If you can't keep the fuel/oil off the paint, consider coating the areas that are likely to get exposed with a gas proof material - I have heard of others using polyurethanes, (such as used on floors, outdoor furniture, etc - again, low VOC content) but have not tried this myself, yet.

I'm looking to first understand if there is something wrong with my engine setup. The engine runs great at all settings. I cover the right inboard wing, fuse side and gear with newspapers before running the engine (cowl off) - after 10 minutes of run time, the newspapers are soaked through to the point that I still get fuel/oil on the paint. This just doesn't seem right.

Received the prop adapter from CH, with the single bolt adapter. Had to machine the hole for the magnet, myself, but this was easy to do once I got the right drill and reamer.

I've run the engine now with Master Airscrew 24x10 (inexpensive place to start). I'm getting about 500 more RPM out of it then the Byron 3-blade prop, and what feels like a lot more thrust than the RPM increase alone must be providing - I expect it has alot to do with the stiffer blades than those found on the Byron prop.

I plan to try a 24x8 and perhaps a 22x8, next.

I have one question left. If you or anyone else has an answer, would like to hear it.

I'm looking understand if there is something wrong with my engine setup - it spits an unreasonable amount of raw fuel/oil from the carb. The engine runs great at all settings. I cover the right inboard wing, fuse side and gear with newspapers before running the engine (cowl off) - after 10 minutes of run time, the newspapers are soaked through to the point that I still get fuel/oil on the paint. This just doesn't seem right.

I've not seen anyone at my club having this problem on their gas engines, nor have I ever had this issue with any of my yard equipment (chainsaw, line/hedge trimmers, etc.). The engines on my yard equipment are of course equiped with air filter systems - perhaps this is the difference.

Any ideas?

Some of the Precision Eagle engines had the bottom of the piston skirt cut off on one side about 1/8" to get more intake duration...If yours is one of those the piston skirt doesn't cover up the intake port early enough to keep some of the charge from coming back out the carb at lower rpms......You might try a velocity stack with a 45 degree angle facing forward....

Thank you for the feedback - I'm learning something new about this engine, seems like every day.

Is a velocity stack something I can purchase somewhere? I believe this is a Walbro carb on this engine. Will check Walbro site, too.