DerJET EA6b Prowler build
07-31-2018, 10:50 AM
#26
I appreciate your concerns, your unable t see in the picture but the elevator servo tray is typical 3 ply plywood 1/8" thick, reinforced in the are of the servo with a 2nd layer of 1/8" plywood, total of 1/4" thick, very rigid with a lot of load distribution so not concerned structure in this area, and yes I have lost a 3d airplane when the rudder servo mounting tray failed, so I am sensitive to this issue.
The elevator control arm is almost 2" tall, very rugged, and your right the final location of the rod end on the servo arm has yet to be setup, I want about 20 degrees of up elevator travel at 100% travel, that's my plan to determine the hole on the servo arm that will get used. FYI the full scale Prowler flight manual states 17 degrees of elevator travel normal with 20 degrees available for spin recovery, so that's my plan on elevator travel dual rate setup, should be plenty. I will use the hole closest to the servo pivot to get maximum leverage, this servo is rated at almost 700 in-oz. of torque and I want it all.
The elevator control arm is almost 2" tall, very rugged, and your right the final location of the rod end on the servo arm has yet to be setup, I want about 20 degrees of up elevator travel at 100% travel, that's my plan to determine the hole on the servo arm that will get used. FYI the full scale Prowler flight manual states 17 degrees of elevator travel normal with 20 degrees available for spin recovery, so that's my plan on elevator travel dual rate setup, should be plenty. I will use the hole closest to the servo pivot to get maximum leverage, this servo is rated at almost 700 in-oz. of torque and I want it all.
08-05-2018, 06:00 AM
#27
Thread Starter
A quick plug for availability of the Prowler in the US, contact Eric Clapp for information. Last week was a slow week on the Prowler, but a great time flying with the guys up at Custer airport, what can I say it is summer, will take some pictures and update later today.
08-05-2018, 09:07 AM
#28
Thread Starter
As stated slow week, but things did get done, little bit every day. Sealed the turbine bay with finishing resin, routed the landing gear air lines, and started gear door air line routing. Up front under were the cockpit will eventually go equipment layout has begun, the front bay will have batteries above and below the plywood tray, have (2) turbine batteries, 3 cell LIfe, will fit below the tray if feasible, and (2) 2 cell LiPo for the radio systems. Behind that will be the Powerpacks for the turbines, all above the tray for easy maintenance and inspection. The 2nd bay is consumed by (2) large air tanks, nicely fitted so no reason to change this convenient location. The 3rd bay, behind the nose gear well, between the inlets is for electronics. The Spektrum 20 channel receiver is up front and center, again on top, and room is provided for a gyro directly behind the receiver, come on Horizon get some of those new A S3000;s in stock. The plywood trays mounted on the inlets are for (4) Xicoy dual action valves for all the air systems, that's retract, gear door 1 for strut doors that stay open with gear down, and gear door 2 for the main gear wheel doors that close after gear extension, and of course the speed boards are the final dual action valve. All these systems will be hidden by the cockpit.
09-14-2018, 03:43 PM
#29
Thread Starter
Been a good month, traveling, visiting, and flying jets so I’ve been a bit lax on the Prowler project, but not completely out of it. So an update, all systems less the turbines and fuel systems were installed, programmed and tested, all that was remaining this week was to install the turbines when they got here along with the fuel tanks, and UAT’s. Well it happened, a break in my travels and my new pair of Jet Central Hornet turbines showed up Tuesday afternoon, to the remainder of this week has been 100% effort on completing the Prowler.
The tailpipes showed up also, still no cockpit that won't stop the Prowler from flying, so big push to the end.
The tailpipes showed up also, still no cockpit that won't stop the Prowler from flying, so big push to the end.
09-14-2018, 04:50 PM
#30
Thread Starter
Twin Hornets, started right off with no issues, great running little beasts.
How's this for some twisted tailpipes, "S" pipes turn out to the sides then angle back aft, pretty nifty setup.
Got the two Jet Central Hornet installed, 85 Newtons in a turbine the diameter of a Super Bee, light and powerful, might have to try one these in my Vampire, 19 pounds of thrust is what I started flying her on with a first generation Rabbit, so a smaller, lighter Hornet with the same 19 pounds of thrust, makes you dream.
09-14-2018, 05:05 PM
#31
Thread Starter
The recceiver is located at the aft end of the cockpit bay, buried between the inlets. I don't yet have a gyro installed, but you know it is coming, just not before the test flight. Still need to tidy up this mess of tubing and wires, but not too bad for initial install.
Up front is reserved for the heavy stuff, that tray weighs 4 pounds 10 ounces, just batteries and PowerPacks. The yellow batteries are Jet Central supplied 3c LiFe 2100 mah for the turbines, and blue are 2c Lipo 2200 mah for the radio.
Now the forward bay, since I don't have cockpit yet I moved everything forward to get the CG right, shooting for a 15% static margin so to get that needed everything up front. I suspect when I get the cockpit some items will relocate aft. What you can't see in the pictures are the two UAT's located up in the nose cone, that's another 10 ounces up front, finalized my target CG with no ballast.
10-03-2018, 05:42 AM
#34
Thread Starter
Actually you won't see the maiden, I have 11 flights on her so far, wonderful flying airplane, smooth and precise for a scale jet. The long fuselage, and especially the long tail makes for a nice aerobatic airplane, that is without the ordinance hanging under the wing, with that extra drag and turbulence she still flies well, but it does reduce the aerobatic precision.
I've been troubled with a main landing gear issue, development thing, but believe I have it straightened with 4 flights in a row with the main landing gear fully retracting.
Good news, my estimated CG at 15% static margin worked out well, slightly nose heavy, something I plan on working on during the next few flights as I can now start working on the final setup, all those aerodynamic calculations work well.
The Prowler surprised me with the spoilerons for roll control, they are very effective, I am flying in what I had setup as low rate, very effective including inverted in aerobatic maneuvers. The full span flaps also really create a lot of drag when lowered to a full 30 degrees along with the gear for landing, approach control with throttle is similar to my Vampire, carrying about 1/3 throttle in the landing configuration.. Simulated single engine flight has been completed also, very none eventful, no rudder correction at cruise speeds, landing approach speeds I did use rudder to maintain straight yaw trim with enough confidence to continue all the way thru approach and landing, very nice handling for a twin, better than an A-10 on one engine.
I need to lock in my control throws and setup, particularly spoileron to flap mixing simulating aileron differential to improve axial rolls, currently similar to a Eurosport corkscrew and high rate, but amazingly axial at medium and slow rolling. I plan on bringing the Prowler to Rosewood next week as she is flying very well.
I've been troubled with a main landing gear issue, development thing, but believe I have it straightened with 4 flights in a row with the main landing gear fully retracting.
Good news, my estimated CG at 15% static margin worked out well, slightly nose heavy, something I plan on working on during the next few flights as I can now start working on the final setup, all those aerodynamic calculations work well.
The Prowler surprised me with the spoilerons for roll control, they are very effective, I am flying in what I had setup as low rate, very effective including inverted in aerobatic maneuvers. The full span flaps also really create a lot of drag when lowered to a full 30 degrees along with the gear for landing, approach control with throttle is similar to my Vampire, carrying about 1/3 throttle in the landing configuration.. Simulated single engine flight has been completed also, very none eventful, no rudder correction at cruise speeds, landing approach speeds I did use rudder to maintain straight yaw trim with enough confidence to continue all the way thru approach and landing, very nice handling for a twin, better than an A-10 on one engine.
I need to lock in my control throws and setup, particularly spoileron to flap mixing simulating aileron differential to improve axial rolls, currently similar to a Eurosport corkscrew and high rate, but amazingly axial at medium and slow rolling. I plan on bringing the Prowler to Rosewood next week as she is flying very well.
11-30-2018, 08:33 PM
#36
My Feedback: (30)
Actually you won't see the maiden, I have 11 flights on her so far, wonderful flying airplane, smooth and precise for a scale jet. The long fuselage, and especially the long tail makes for a nice aerobatic airplane, that is without the ordinance hanging under the wing, with that extra drag and turbulence she still flies well, but it does reduce the aerobatic precision.
I've been troubled with a main landing gear issue, development thing, but believe I have it straightened with 4 flights in a row with the main landing gear fully retracting.
Good news, my estimated CG at 15% static margin worked out well, slightly nose heavy, something I plan on working on during the next few flights as I can now start working on the final setup, all those aerodynamic calculations work well.
The Prowler surprised me with the spoilerons for roll control, they are very effective, I am flying in what I had setup as low rate, very effective including inverted in aerobatic maneuvers. The full span flaps also really create a lot of drag when lowered to a full 30 degrees along with the gear for landing, approach control with throttle is similar to my Vampire, carrying about 1/3 throttle in the landing configuration.. Simulated single engine flight has been completed also, very none eventful, no rudder correction at cruise speeds, landing approach speeds I did use rudder to maintain straight yaw trim with enough confidence to continue all the way thru approach and landing, very nice handling for a twin, better than an A-10 on one engine.
I need to lock in my control throws and setup, particularly spoileron to flap mixing simulating aileron differential to improve axial rolls, currently similar to a Eurosport corkscrew and high rate, but amazingly axial at medium and slow rolling. I plan on bringing the Prowler to Rosewood next week as she is flying very well.
I've been troubled with a main landing gear issue, development thing, but believe I have it straightened with 4 flights in a row with the main landing gear fully retracting.
Good news, my estimated CG at 15% static margin worked out well, slightly nose heavy, something I plan on working on during the next few flights as I can now start working on the final setup, all those aerodynamic calculations work well.
The Prowler surprised me with the spoilerons for roll control, they are very effective, I am flying in what I had setup as low rate, very effective including inverted in aerobatic maneuvers. The full span flaps also really create a lot of drag when lowered to a full 30 degrees along with the gear for landing, approach control with throttle is similar to my Vampire, carrying about 1/3 throttle in the landing configuration.. Simulated single engine flight has been completed also, very none eventful, no rudder correction at cruise speeds, landing approach speeds I did use rudder to maintain straight yaw trim with enough confidence to continue all the way thru approach and landing, very nice handling for a twin, better than an A-10 on one engine.
I need to lock in my control throws and setup, particularly spoileron to flap mixing simulating aileron differential to improve axial rolls, currently similar to a Eurosport corkscrew and high rate, but amazingly axial at medium and slow rolling. I plan on bringing the Prowler to Rosewood next week as she is flying very well.
Thx in advance
12-01-2018, 11:48 AM
#37
Thread Starter
There is a nice video over on the Fall Jet Classic post page on Facebook, think I'll have to fly her again on the next clear day up here in NE Ohio. Love the way the fuselage splits in two so easily, fits in the back of my 6'6" pickup truck bed nicely.
https://www.facebook.com/Fall-Jet-Cl...0975395/posts/
https://www.facebook.com/Fall-Jet-Cl...0975395/posts/
01-21-2019, 02:45 PM
#40
Thread Starter
How about four ejection seats, I'm going to need a pilot and 3 crew to fill these pits.
Just got hooked up with the cockpit, what well detailed package, it sure looks good laying in place. The cockpit is the usual plastic assembly we've come to expect, though I will beef up the tubs to make a robust structure as, with my install, I will be removing it after every flight for refueling. This cockpit fit right in place in the recess surrounding the canopy opening on the fuselage, no trimming or fiddling required, sure can't beat that.
I think is coming time to bring the Prowler down in to the work shop for cockpit install, detailing, and of course a bit of light weathering.
01-21-2019, 03:02 PM
#41
Thread Starter
You know how we are always worried about single engine flight with twins, well I got my first real taste of that this year, had the right turbine shutdown as I left the ground on takeoff, cold weather issue. I was in denial and really didn't believe I had lost power on one turbine, climb out was not as steep as normal, but I did leave full power on instead of climbing out at reduced power like I normally do. I also noticed my rudder trim was off, yeah I had to be flying on one turbine. I trimmed in a bit of left rudder, only yaw correction needed as I circled the field a few times to make sure everything else was normal, than landed the Prowler shooting the landing pattern and approach like any other landing, normal speeds all the way and carried power all the way in to final, then throttle off at about 10' and executed a normal full flap landing, well except for the that left rudder trim I had added now showed up as out of trim in yaw. Surprising to me I don't remember carrying any additional rudder correction throughout the landing pattern and approach, this airplane handled it well. Two things I will admit, I was very smooth on the controls, no abrupt elevator or aileron moves, and I did not have a gyro plugged in for this flight, the gyro wasn't working properly on the ground in the cold weather so I unplugged the gyro and flew anyhow, who needs a stinking gyro anyhow, and the Prowler proved on this flight it doesn't need a gyro.
10-24-2019, 07:46 AM
#43
After meeting Jack from DerJet face to face at JetPower for the first time in 10 years of business (really nice guy) we decided I should put a Prowler together over the winter. The kit has arrived and I must say the quality is great again from DJ. cockpit is huge-looks great and gear is a work of art. I've not decided which way I'm going on turbines yet. I will be a slow burner as I have other things to finish first. Expect a test flight beginning of next season.
10-25-2019, 12:06 PM
#50
