ESM 88” Zero – Maiden Flights

My warbird has a peaceful day

Text and photos by Tom Hintz

Flight video by Clark Ponthier

Posted – 10-12-2015

The thing that worried me most about the maiden flight with my ESM 88” Zero was that 2-1/4lb of lead I screwed into the nose area. The fact that my EZ Balancer said the CG was perfect is reassuring but I needed to get the ESM 88” Zero in the air to really convince myself.

Of slightly lesser concern was that this would be the first time I had flown an RC plane in about three weeks due to weather. Here again, things worked out for the better. I was able to keep up with what the ESM 88” Zero was doing and I got it trimmed out pretty well during the first 5 minute flight. The 5 minute flight time was a “safe” guess to start with considering the 18.5 oz (550cc) tank. The last flight on maiden day went well into the 5th minute before landing but when taking the wing off I found roughly half a tank of gas left over. I will take the timer to 6 minutes for the next flight day and see what is left then. I do not want to set myself up for a dead stick with a warbird so will sneak up on the maximum safe flight time.

First Flight

We had a fairly stiff 90-degree crosswind for the maiden flight and that along with the left wheel sucking some grass between itself and the axle washers helped the ESM 88” Zero make a hard left when I got on the gas. I had another 20 feet or so of runway width before I hit the tall grass next to the field so with the DA50R coming on strong and the tail already being up I gave it a bit of elevator and cleared the grass easily. My friends watching the maiden got their only “holy cow” moment of the flight right then.

At speed the ESM 88” Zero wanted to balloon and it took considerable down trim to get that under control. There also was a tendency to roll left that was fixed with 5 or 6 clicks of right aileron. The ESM 88” Zero has different responses to the elevator settings between slow and fast. With the elevator trimmed to level flight at speed the ESM 88” Zero tends to nose down at lower speeds like landing approaches. This is not difficult to manage if holding a bit of elevator during landing is not scary to you. This elevator change could also be managed with different flight modes for normal flight and landing. I like having a “flight” mode where the engine idle is increased by 5 clicks of trim as insurance when I go to low throttle during the flight. Then I click into “landing” mode where the idle comes back to normal to slow the plane. I can add elevator changes to those flight modes and make all of this easy to manage.

Rudder is reasonably effective at all but very low ground speeds and the ESM 88” Zero does not seem overly sensitive to rudder in flight. I didn’t stuff all of the considerable rudder throw I have dialed in but did give it a good amount to support a banked “warbird pass” with no ill effects.

The ESM 88” Zero responds to aileron input like a warbird rather than a typical aerobatic plane which is to be expected. If you are accustomed to the roll rate of a 3D or even sport planes the ESM 88” Zero will feel kind of dead but again this is typical of war birds. However, rolls do not need as much down elevator correction as I expected to keep a roll on line. Elevator response during rolls remains very good so doing a victory roll as you pull up from a low pass is easy and looks very realistic.

Flaps

The ESM 88” Zero is far more responsive to the flaps than I anticipated. I had half flaps set at about 32 degrees and full flaps at 55 degrees or so. On the first approach with full flaps I had to hold some down elevator (didn’t have any down programmed in the flap system yet) and while it was settling in towards the runway remarkably flat the flaps were doing too much braking and it was losing too much airspeed. I pulled the flaps up and went around and used half flaps the rest of the day. Before the next flight day I will change half flaps to about 15 degrees and full flaps to 35 degrees, each with a down elevator value of 5 to start with.

The ESM 88” Zero does land fairly easily if you keep the speed up and land it on the mains. I have a Vess 23B prop on and there is very little ground clearance, especially with unusually tall grass we had on maiden day at our field. Flying the tail on landings (and take off) is easy as the elevator remains effective at the lower speeds.

Robart Retracts

With the maiden day under my belt I remain very happy that I chose the Robart electric retracts for this project. They fit and installed easily and being powered through the receiver they worked perfectly all day. The speed at which the retracts work is very realistic which means they ain’t quick! The speed of the up/down cycle will only be a concern in situations like a low dead stick when a belly landing might be a better plan.

The Robart retracts have roughly ¾ to 1” of compression built into the struts and that seems very well designed for my 20lb ESM 88” Zero. I have 4” DuBro wheels on and combined with the Robart retracts the ground handling is very good. I did get the prop into the grass enough to stop the engine a couple times but the grass was exceptionally tall for our field due to a bunch of rain recently. I think that given normal grass height the ESM 88” Zero will do just fine on landings.

Conclusions

Overall the ESM 88” Zero does not have any bad flight tendencies with the CG located per the manufacturer instructions. It flies easily for a warbird and looks very scale in the air. However it is a 20lb warbird with a scale wing and flying characteristics so should not be thought of as a trainer. Experienced pilots should have no problem flying the ESM 88” Zero in normal conditions.

I have a friend that flies the ESM 88” Zero on a DLE35 and his exceptional skills on the sticks make it look good in the air. I think the ESM 88” Zero likes the DA50R much better. The extra power makes take offs easier and you can control landings more easily also. In flight you get superior scale flight with the DA50R more or less loafing most of the time. I like it when the motor is not straining to keep a plane in the air.

With a street price of $519.00 (10-12-2015) the ESM 88” Zero is not bad as war birds go these days. The fact that I had to add 2-1/4lbs of weight is also not uncommon in war birds that retain scale dimensions. The instructions are marginal on a good day and the prescribed pull-pull system is just dumb. Steel cables looped through steel control arms at the tail are a prescription for a crash. Use something like the Sullivan cable system with ball links on all of the ends and the ESM 88” Zero is a far more reliable plane.