At our field
We love the DLE 55
BUT
several of us have converted the prop adapter to a single bolt
which after a while are breaking the bolts that hold the adapters on

Does anyone else have this problem with the prop adapters

we have use adapters from two different sources
???

Sounds like the adapter is slipping. Have you tried to maybe glue either a piece of 150 grit sand paper on the back part of the adapter or put about 3 small dabs of goop to prevent the adapter from slipping? Give it a try.

Is the 4-bolt hub that much of a problem?

I think you will find very few of the 3D guys convert them, though my GT-80 is single bolt and its been fine.

Lifer
YesI am extreemeeely lazy

91 Zulu
We have tried little bit of everything Red-thread sealer
there are about 9 Dle at our field with the adapter
4 have broken off the bolts

Sounds like an easy fix. Use the engine as designed.

WELLLL
when an item is sold to make the product easier to use
it should be able to be used safely
and
I thought I would ask on here if everyone is having a problem with this item
that would let Others know of a problem and NOT purchase the item
or
someone could suggest a solution
just trying to help others not make the same mistake several of us have been having
It is easier to learn something and to have to experience everything first hand
share the knowledge

Lots of help bu OldScaleGuy I see.

I hate that so many of these engines have the multi-bolt hub. It makes lining up the spinner backplat, prop and spinner cone a bear to fit together. It's not a problem is you use the single thru bolt to hold a cone on, but when you use perimeter screw to hold the cone on, it becomes a bit of work.

I am guessing that the bolts are coming loose, another common problem it seems with these multi-bolt hubs; especially if you are using a wood prop. Can you get a lockwasher under the bolt head that will fit in the adapter recess? That's another interesting feature, many of these multi bolt hubs allow for the bolt head to recess, but not get a lock washer under it. It's beyond me why they would make it that way. If you can get a lock washer in there, then try these, I got introduced to them by a guy from over the pond. You can get them at McMaster-Carr: Nord-Lock Washers http://www.youtube.com/watch?v=mgwmuZuJ02I

Jeff

I installed a single bolt prop adapter on my DL 50 this last summer. Since the bolt heads are tapered, there is no way to get a lock washer behind them.

I think there are only 2 things that could cause this. The bolts getting loose, or the bolts used to fasten the adapter are not of the right grade/hardness. I know Hobby King sells these, very cheap. The bolts probably are too!

The instructions that come with the Valley view unit are very specific about type of thread lock and torque. I wonder how many that have broken were either the Hobby King variety or the directions were not followed properly?

It is imperative to get the original prop stud below the thrust washer on the engine. If the new prop adapter makes contact, it will not seat properly and break.

Jodi, from Valley view commented that he had only seen one failure and this was the reason why.

Great service by Valley View is they will install this for you when you buy the engine. That is a great deal as it is not the easiest thing to do. I think it took me around an hour to convert mine.

Has anyone tried teflon tape on the threads. Also how big are the holes in the adapter? Is there a lot of space with the locking bolts in the hole. Some times the holes in the adapter are a little too big. If the holes are fine change the bolts to a higher grade and use Teflon tape on the threads. This is similar to the Super Tiger issues of losing mufflers in flight because the bolts keep backing out.

1 was hobby king, it was mine, I threw away the screws that came with it and replaced it with high quality bolts
They broke
1 was from valley and installed by them
it broke loose also

there is not room for teflon tape
and V G is right the bolts are tapered and can not have a washer behind the bolt

Thread lock was used in all cases
Our conclusion is the bolts worked a little looseafter they became loose it was just a matter of time
a complication is they were all behind spinners so they were not check for looseness after flights

So far seems like I have heard from guys that dont use the adapter
This was over time like weeks or months after intalled

How about you guys that are using the adapter
do yours come loose and break -???

Looks like this is something that must be checked occasionally. If the bolts come loose, then it seems like a guarantee for a failure. The teflon tape on the bolts is an option, but would this perform better than the right thread lock?
We mostly have gassers at my airfield and most are running them stock. In fact, I may be the first one to have installed the adapter. It is just so convenient, I really like it.

One thing to keep in mind when considering installing one, it moved your spinner out the thickness of the base of the adapter. This is around 3/16". I had a nice tight reveal at my spinner with my cowl on my warbird and this modification screwed that up. I may modify my stand offs to move my engine back to fix this.

I'm sure those bolts got loose and that's causing the bolts to break. They might be getting loose from a poor fitting taper/counterbore whaterveryacallit? Material they're made from to soft?

I've got a Brison with the factory installed adapter that's never ever given a hint of trouble. Looks like it was made by a gunsmith, real, I mean REAL quaility item!

No....but my 55's are soft mounted on rubber isolation mounts. Vibration is absorbed and never gets to the bolts

I would think that you would be dealing with centrifugal forces here, and not vibration(although that could compound the issue).  If it were me I would replace the bolts with a higher grade and check every couple of flights.<div>
</div><div>Just an opinion....</div><div>
</div><div>Casey</div>

This thread is mis labeled. Not a dle problem its a lazy problem. Zenoah guys get away with it because they dont make much power. A dle55 will waste a gt80 at half throttle.

The multibolt hubs are not a "tighten and forget" item. You are supposed to check the tightness of the bolts ever so often to ensure they are still tight.

Soft mounts dont isolate an engine from vibration either, since it is the engine that is the source of the vibration.

I agree. I have a DLE-111 and a 3W-150, my wife reminds me regularly to check and tighten the bolts. (that is not a complaint at all, i appreciate her being safety minded). Oh by the way, both of those engines have 6 bolt hubs.

+ 1 invertmast !!!!!

The soft mount thing !!! well does it not say helps to not transfer VIB to air frame !!!

if thay dont wont to drill 4because it is EZ er Iwonder if thay take time to balance the prop ????

a lot of things going on hear the little DLE 55 I wonder some times why it works so well

The oil thing all ways makes me CRAZYalso BOOK 30 / 132 / 1 safe people any where from40/ 50 and

even 100 to onesometimes and people seamto blam the thing when something goes rong !!!

doall of them come with a book or just some of them???? $0.02 R/L

I agree with Oldscaleguy. You may just need to work the problem instead of solving it. You might try ordering a bag of 100+ screws from Microfasteners and replace them monthly during your flying season. If you know its a high stress area it my be all you can do.

Jeff,

I assume the issue is replacing a broken prop

The way I've done it is to use the back plate as your alignment jig, Use a center bolt to temporarily hold the prop to the back plate and get the spinner screw holes aligned,, then once the spinner is on and you like where it is, drill part way through the back plate holes,,, then you can disassemble and drill with the proper drill jig and drill press the remaining holes,, The spinner should be aligned perfectly.

good luck

Or you could just buy the $20/30 prop drill jig that nearly every manufacturer has for their engines now.

It still amazes me how people in this hobby will spend weeks and $50+ trying to make something "easier" by redesigning a known working design only to have it fail, when there is already an easier way of doing so.

A VERY bold statement there! Would you care to back that up with some facts? I have both engines. The GT-80 out swings the DLE-55 with a NX 24x10 prop easily running from the same gallon of gasoline/mix.

I would like to see someone show up at a Formula 1 GT-80 class Pylon Race with a DLE-55 ( in any configuration on a spec airframe ) powered plane to compete against the GT-80's. I think you would have to eat your own words.

Granted the GT-80 is heavy and not really suited for 3D but it is a superb engine as is the DLE-55 and both engines have their place as far as application.

Show me a DLE-55 that will turn 11K+ on a APC 18x12 ( and hold together! ) and I will back off my post.

Speedy
your correct jeff- had four sentences and four incorrect statements
I also own a GT 80 and a DLE 55 both are great motors but
the 55 is not in the power range of an 80

Just to add some fact to my proclamaition...I have personally owned/flown the DLE-55 side exhaust and I now own/fly the new DLE-55 RA rear exhaust and the DLE-55 RA is a bit more potent but still the GT-80 has the upper hand on power. My GT-80 has been converted to Rcexl ignition and about a full pound has been taken off the weight. I am very pleased with the Zenoah and it is one of the most consistent and best running engines I have ever owned plus it is very smooth being a twin. I looked at the DLE-60 twin but the Zenoah GT-80 is actually narrower in cap-to-cap width. It has a single bolt hub and no problems with broken bolts.

I run the stock 4-bolt hubs on my DLE's BUT I do replace the stock bolts that come with the engine with quality USA made bolts. I have checked the Hardness ( Rockwell "C" ) and they are substandard and they will stretch which is probably the reason for failure.

Soft bolts will, even over short periods of time..... stretch,work harden, and fracture, most frequently in the threaded area of the bolt. Everyone complains about Chinese bearings. Well....Chinese bolts aren't much better! [:'(]

Speedy-Gonzales