Lanier Predator - Experiences and Modifications

I built 2 Lanier Predators for 424 Q-500 to compete in a local racing series in Omaha .

Here are a few modifications I made based on other's experience. Most of these changes were taken from Darrol Cady's website, www.darrolcady.com :

Thanks Darrol

1) Used the pizza cutter wheels from Darrol.
----Why? They look cool and many have mentioned they are far more durable.

2) Tetra tank
----Why? I'd like to get back into 428 Q500 and Q40. These tanks are SOP and I thought this would be a good way to learn how to use them. Totally necessary for these engines? - probably not.

3) Carbon fiber pushrods
----Why? Another teaser on Darrol's site I had to give a try. Worked great.

4) Elevon pushrod holes under stabs
----Why? Seemed like a simple upgrade and cleaned up the tail of the plane. Not necessary but not much tougher to do. If this were my first Q500 I would have set it up per the plans. Pull on a control surface is better if everything isn't just right. I did not use the ball links because I couldn't find any at my LHS that would fit the 4-40 all thread. The set up I used is similar to an aileron connection.

5) Added reinforcement: Added epoxy and cabosil to beef up the landing gear block and the firewall. Years ago we found milled fibers made into a fillet was the best method for adding strength to these joints. Glass just tears at the corner due to the stress concentration from the 90 degree angle. I couldn't find any milled fibers but had some cabosil so that's what I used. I also added the tri-stock under the wind hold downs.
----Why? Nothing is more frustrating to have a day ruined by puking a firewall out on the runway or ripping the gear off after a botched landing.

6) Used G10 for the throttle and switch mount as well as the servo spacer for the elevon servos.
----Why? I had some scrap G10 laying around from my AVENGER. It worked well here to.

7) Re-tapped the wing hold threads for 1/4-20 bolts and hardened the holes with foam safe CA.
----Why? It was recommended and what we used in the past.

8) I set the CG at 2-3/4
----Why? This a fairly conservative, but not overly conservative CG location. Provided crisp elevator with minimal throw.

Here's what I did different on my second Predator.

1) Extended the elevon attachment points further from the control surface. More leverage put less stress on the servo. I lost a servo on my 6th flight. It was a servo that has seen a little action in combat but may have gone south due to the short control arm length. Bought a fresh Hs-225 today and it failed later in the season. I brought it back fine both times, but was lucky I had extra in my dual rates. I banged it a little hard but it held up just fine.

2) Checked the tail incidence and work to get it closer to zero. I made the mistake of measuring the sides and neglected that the front of stab sits lower. I realized I screwed up later. It ended up with 2 degrees negative and carried about a 1/16” of down trim. Not a huge deal and it wasn't tough to shim the front of the stab before it was glued in on the second one.

Here are some pictures.

These pictures can also be viewed in the TEAMseaholm Photo Album under the album titled Lanier Predator.


 
Published: 11.14.2004