ZDZ 90, Install into new EF 94" MXS

So I was talking with Joe at zdzusa.com about some other stuff and he brought up the 90 single now being in stock. I had previously read several reports from @tbrum on the canadian forums about the smoothness of these engines. Joe confirmed this after doing a re-build of one and running it on a test stand.

So this summer I was on the lookout for an airframe to try out one of these bad-boys for myself. Since the trend for many airframes is going larger and larger, I started running some numbers on wing loading and comparing to my experiments this past summer. "Some of you may remember I built new wings and converted an 88" Edge to a 91" with an 85cc power plant."

After traveling to the Taildragger Extreme 3D event, I knew I had found the perfect plane to test this engine. The 94" EF MXS is perfectly proportioned for a larger engine but it takes a little planning and for-thought to make it work properly. The only thing I would change is to have dual servos in the wings, which can be done but I will test it as is first before going in for surgery.

Here are some un-boxing pics from the 90 and comparing to the engine that is meant to go into this plane. And.....just for fun the weight of a DLE111 that funny enough would also fit in this plane, the cowl is huge:

Pics of engine install and start of plane assembly. Pretty much electronics and ready to roll at this point. I forgot that I had to order a new prop because it has to be indexed for this particular spinner so with luck that will show up by the weekend for some test flight.

More from today. Very important on this type of cowl to get proper air flow at the cylinders (baffling is not even a question, it MUST be done!!), whether running the 70 or a large single. I did a partial baffle to make sure that ALL air coming into the front hole is going through the fins. I also decided that since the muffler on this engine is large, I made some cylinders from foam and aimed the air coming in back at the muffler to cool it, and also get that air aimed towards the exits.

I forgot the terryscustom disclaimer:

NOTICE: This setup is not for everyone. I consider the warranty as null and void on any ARF airplane that I build as soon as I open the box and check over all the parts to be damage free. This engine is spinning the same prop as a DA100 at about 50rpm's less according to info I've been given. This means that it has power enough to cause structural damage if not flown with a good understanding of how and when to use this power!

Looks awesome. Can't wait to see that engine running.

I have had problems with air flow with the big mufflers behind engin not letting air out of fins.

1932 said:

I have had problems with air flow with the big mufflers behind engin not letting air out of fins.

Click to expand...

Yup, notice what I did on the top two snorkel holes. Air blown directly at the muffler and aimed directly at the can tunnel to promote air flow. Also notice the 3/4" tall low pressure lip on the belly side. This creates a venturi effect and actually pulls air through the system. With these two things, I expect air to accelerate as it gets through the engine.

The one thing I do foresee is re-starting the engine after a run. It will have to sit for a bit, because with the large can in there heat will build up after shut-down. I've had this with other singles with large pitts mufflers though and it's not a huge deal unless you anticipate flying back to back.

Very interesting Terry was taking a long look at this plane at joeNall. Will be following this thread.

It is looking really good ! The power to weight ratio of this airplane is going to be fun !!!