Ted62

My Feedback: (2)

Hi Chorner; No appolgies needed - I appreciate any and all comments/suggestions! That's why I check in to the forum. Unfortunately, since he accident happened on only the second flight, I really haven't had much time to investigate the flying envelope with and without flaps - in fact, the accident happened on only my second landing (attempt-LOL). I made the mistake of standing at the opposite end of the runway and the old depth perception thing got me! All's well that ends well, however; the plane will be in the air again very shortly - Callie is shipping a set of checkers for the cowling and I have 2 small holes to drill yet - then, it'll be ready to fly again! Wondering if anyone has a source for a flex cable to connect the needle valve to the outside of the cowling.

chorner

Nice Ted! That was quick to get her all back together and ready to go The checkers should help visibility too. One thing I've found with mine is against a bit of a cloudy sky, it's very hard to tell which wing has dropped for general orientation. Not the most visible plane in the air that's for sure!

I was looking for a needle value extension myself; ended up ordering a couple OS needle extension sets (I believe it was for the FR-5 300 radial), and used an appropriate diameter brass tube to join the two together by crimping and soldering the end of the brass tube to the extension on both ends. I then put a length of heat shrink over that, to stop any rattling against the Keleo exhaust from scratching everything up.

Ted62

My Feedback: (2)

Thanks!! I just ordered 3 from Tower - that will work!

njmheli

Hi All.

Well,all finished on the "construction" side of things...........should be able to complete my c of g in a couple of days...........then will have the all important AUW ( less fuel ) !!!

I will do a couple of engine runs in the back garden,then off to the strip ( when the weather is good for the maiden ),in the meantime,will dust off my H9 60size Corsair and get some flying in...........may help !!!

Anyway,will keep you all posted,this is a great forum...............nice guys and lots of ideas and help available to all..............PERFECT !!!

So,thought I would use some "space" up and post the finished Corsair...........

Regards...................Nick (UK).

steph69

beautiful

Ted62

My Feedback: (2)

Great job, Nick. I never kept track of my time - did you? Being an "ARF" - I'm sure it was less than 20 hours. (Maybe 20 squared!!!) LOL Very anxious to hear your final dry weight and where the CG falls. I didn't trust the vanessa (even though it seemed to be close) - my son (40 yrs old) bench pressed it while lying on the garage floor to double check it. We plan to do it again this week some evening as soon as the final vinyl graphics are added to the cowl. Best of luck on the maiden which I'm sure will be soon.

Ted62

My Feedback: (2)

Btw, Chorner, the picture I posted a couple frames back was before the maiden - (pre-crash). However, it will be very close to that in a week.

Todd D

My Feedback: (51)

Guys,
A few posts ago I mentioned that I would take the wing off for inspection after the maiden flights. All seems to be OK but I did notice something that may be concerning. Take a look at the attached photos. The hole where the bolt comes through to attach thte center section to the wing seems to be a bit thin and maybe pulling through. Do all the planes look like this? Do I have a legitimate concern about the wing coming off in flight?
When I assembled the plane I put a flat washer down in the hole followed by a lock washer then the bolt head. Seems the hole is starting to "mushroom" out or pull through. (note the yellow object in the hole is the butt end of a small allen head screwdriver holding the washer in place for the photo.
What are your thoughts?
Any Horizon tech reps that may be monitoring the thread, please advise your thoughts as well.
Thanks
Toddd

njmheli

Hi Todd.

Having looked at your photo's,the one thing that is a possibility with your Corsair may be that there is quite a gap between the fitting of the "top surface" of the centre section and the underside of the fuzz ( where the two should "mate",with very little gap if any ) where the captive nuts are secured on that ply bracing,which should be a flat surface to mate on...? This would be particularly hard,if not impossible to see from the top ( looking in from the open cockpit ) as the cockpit detailing stops you from seeing this..?

To me,it would appear that the gap is present as the deformity ( IMO ),could only be caused by either the wing trying to pull itself off the fuzz ( hence your justified concern ) or the deformity being the result of the "top surface" of the centre section,being forced to mate over a bigger gap than should be present at that point of contact for the centre section.

I have had my centre section bolted on only a couple of times ( she has not flown yet,so no structural forces have been put on the airframe ),but it has been bolted down pretty firmly ( but not stupid tight !!! )...........I have no "pull marks" on the top skin........

The thickness of my wood/fiberglass "bolt hole areas" are approx 3 to 4 mm thick............so a fair bit of wood thickness there,but I did apply cyno to the surface at the bottom of the two bolt holes,just to harden up wood in those contact areas and beyond........where the washered two bolts slide down into....I have not used "lock washers" there....if I do use "lock washers",it will be the "Nordlock Washer type"..........

There quite a few of these Corsairs flying now,guess that yours is the first to have this problem to date ( I may be wrong ..? ),as no other similar problems have been reported,pretty sure that this problem would be noticed very quickly by all the flyers..?

Silly question here.............are you sure that nothing has been getting trapped between these "surfaces "...........? Pretty sure you will not have been tightening these bolts way over what they should be.............. causing the wood to be crushed,de-laminating and hence weaker..?

I'm sure that other "thread" uses will also chip in with their thoughts and help............also,as you noted Horizon,should be taking this in.......just in case there is a "flaw" somewhere.............hoping not for all our sake's !!!!

Sorry to hear about this,please keep us informed of your solution or cause.............

All the best Todd

Regards...................Nick (UK).

Fly2XS

My Feedback: (65)

Looking foreward to seeing you at Fondy!
Scott

chorner

Another update on the Robarts & landing gear in general....

A few things I would watch out for after 10+ flights now:

1) before using the Robart mains, I would highly recommend taking them fully apart and using loctite on all screws. Make sure these are nice and solid.
2) keep an eye on possible changes in toe in/out after a few landings. Any sudden changes in toe will tend to toss your plane up on its nose at any decent speed. This could be one of two things: the oleo spinning around where the toe adjustment bolt is down by the wheels or, a sign the cam follower (yoke) that guide the rotation is about to let loose if it hasn't broken completely already.
3) if you're able to do so, make another weld around the pin on the cam follower... you'll be happy you did! These will crack the small housing the holds the pin and either bend, or snap.
4) loctite the tailwheel shock mechanism! This will rattle loose eventually over time... luckily mine rattled lose waiting in the "pits".
5) the tailwheel spring is ridiculously firm, and will not help landings on rough terrain. I found that a spring out of a smaller Robart strut (3/8" for airplanes 5 - 12lbs) cut down by a few mm worked perfectly, and creates a more linear actuation, smoother, and soft enough to provide some actual cushioning. I also got rid of the rock-hard Hangar 9 "Pro Lite" tailwheel, for a Dubro low bounce 1.75" wheel. Much better!

...
6) if possible, smooth out the spring action and also reduce the spring tension on the main struts. I found this just a touch hard as well (but nowhere near as bad as the tailwheel), and softening them up just slightly by reducing the length of the spring also gives much better dampening on grass landings.

All of these things will help soften your landings and keep things from falling apart or doing any other damage. After my 2nd nose over (no damage again, outside of busting a mounting tab in the cowl) because of the "crap" landing gear on this thing, I've taken to doing a complete maintenance/overhaul on them.... and after doing so they are miles better. If only I knew the shortcomings from the start, I wouldn't have had to go back and take everything out, fix it and then put it all back in the plane.

mirored

My Feedback: (1)

I have a new set, first ones built by century jet. I will get them on Monday and see how they are. They have it on their website now. I will provide an update on how they fit and function. These are electric with his updated controller

Zeeb

My Feedback: (41)

Can you say "Sierra"?

Sorry but I have no faith in Robart gear anymore. I've had my issues and everyone I know who has Robart retracts have had issues, especially the poor shmucks who bought the D&L electric conversion.

chorner

I fully agree Zeeb. Robart stuff is garbage. Unfortunately, I've only learned that through this experience, and while I'd love to go Sierra for example 1) I have no room for an air cylinder in my setup and 2) I blew a bunch of money on these Robarts, so I'd at least like to try to beef them up and make them more reliable on my own. .... having said that, if I knew from the beginning all the issues (and had not already purchased retracts) you can bet I wouldn't touch the Robarts with a 10 foot pole

Herc Pilot

My Feedback: (15)

Hi all. I'm new to the thread and haven't read through everything here yet, but figured I'd share my experiences with this plane at 18 flights in hopes that my comments may help someone here.

The setup is..
Evo 77cc radial
McDaniel onboard glow powered by 2x 5000mah nimh batts w/ Booma RC balancing switch
32oz RotoFlow tank
Robart electric retracts w/ recommended Robart controller, wheels, etc.
JR 12 channel power safe receiver
2x 3200mah Life batts
JR 8711 on all surfaces
Spektrum mini digital servos on main gear doors
eFlite lighting and bomb release mechs
Led machine guns, etc.

I won't go into a lot of detail here since I'm sure most issues have been found in this thread by now, but will share my experiences.

The build...
Overall good quality parts. Paint match was good, but center section had been bagged before paint had cured and has left permanent dull spots where plastic bag touched paint. Would not buff out. Center section to fuse and panel fitting is great. The clear plastic lenses for the nav lights did not fit in any way, shape, or form. Rudder was twisted and counter balance didn't match with rudder straight. Twisted with heat to solve. Continuing build showed that most parts fit well. Stab fit was good. Cowl mounting seemed ingenious until flight 18, mentioned later. Hardware was decent, but hinges were sloppy and weak and should not be used. The covering is terrible. Seams are in awkward spots and the covering over the fiberglass parts has wrinkles that cannot be removed. I realize the color is tough to work with for iron on film, but this was among the worst I've seen, esp considering the price tag, you'd expect top quality ARF.

Majority of the build was straight forward. Flaps required much work to move smoothly. Would defiantly recommend using one servo per side. Center-section houses as much radio gear as the fuse. I have 9 plugs to connect when installing to fuse. The recommended eFlite lighting system was installed during build. Looks good at night but you can't even see them during the day. This system seems like it should be on a park flyer of foamy and is almost insulting to put it in a plane this size. Same with the eFlite release mechs. These mechs worked well on the bench but on the second drop attempt, one hung up and wouldn't release (even with spring release) until the plane was back in the shop on the bench where it released fine and no issue can be found. Um, what???? Both the lighting system and bomb releases can't use more than 5.5 volts so will need regulated if using a high voltage system. The cockpit kit and dual canopy option were great. We installed the sliding canopy which worked well. The cockpit floor is a bit flimsy and tight to install so will need reinforcing if a full body pilot is to be used.

Robart electric retracts were installed. The mains initially installed fine and adjusted well using the provided shims. One thing to note is the gear doors. Instructions show 4 pics and little else. You cut apart the flimsy plastic gear doors and each has it's own servo. The servos take some patience to install and get operating correctly and take up any free space in the wheel wells. Servos then must be wired together and sequenced with the mains. Fit of the doors was bad and adjustments were made with a heat gun. If I had it to do over again, I'd make new doors from plywood and form them to the wing. Still they work and haven't needed adjustment yet. The main retracts worked well until flight 15, when the left developed a 'hitch' at mid transition, finally failing to retract fully during flight number 18. The tailwheel mech is sloppy and the actuator failed prior to the maiden flight, shearing away the plastic case its in. Replacement with a new that failed in three flights and my own fix lasted 4 more flights before failing and continuously running the actuator motor. Rear gear doors were also a nightmare to hinge and are wired to the tailwheel with a flimsy spring. I've seen a fix on this with real linkages and plan to use this in the future if a solution for the tailwheel actuator is ever found. Rear gear doors will need constant attention and repair if flown from a grass field.

All batteries were mounted up front as well as the throttle and choke servo. Despite this, one pound of lead shot was added to the cowl ring making the final weight at a portly 32.5 lbs.

Testing and flying
The Evo 77 was initially broken in for 2.5 hours at 15 minute intervals and varied RPM on the Biela 22x10 3 blade. Have ground tested many props and flown with Biela 22x10 3 blade and Menz 23x10 wood 2 blade. Both ended up not being enough pull. Currently fly it on a JC Superprops 23x12 wood. Have a Biela 23x12 carbon but haven't flown it with this yet. I suspect it will be the best prop for our engine/plane combo. The engine has a ton of torque once broken in, but was VERY marginal for power with the incorrect prop at first. Be sure that if you fly this plane with this engine combo you MUST follow break in procedures for the needed power to fly the weight of this plane with any authority. We gained nearly 1000 rpm during break in.

The maiden was performed with gear down since the tailwheel actuator failed after the plane was assembled. A very long takeoff run was needed and nearly aborted and climb out was very slow. Nothing outside of the norm was required for trim but the plane is very doggy and flies tail low with gear out. Flaps help this some, but there is a sinking feeling with the realization that if a flame out ever occurs, there will be no possible return to the field. Three flights were flown gear down that day leaving us very frustrated, but determined to work hings out.

Next trip to the field with two major changes, retracts working, for now, and switched to more bite on the prop with a 23x12 two blade. Now, the planes takes off in about 400 ft flaps up and with gear tucked, the engine unwinds and the plane gets up on step an grooves as it should. After playing with flaps on takeoff and landing, it shows that takeoff roll can be reduced greatly using mid to full flap and with gear down, flaps should be used to replace the lift lost when dirty. Landings are easier with a little speed and should be wheel landed in ground effect rather than attempting a full stall or harrier type landing, which I feel some pilots with lesser experience may try and will be the demise of many of these birds. Subsequent flights show a consistent low speed threshold with a mild tendency to drop the left wing if flare until full stall while in ground effect. While this engine paired with this plane is very scale and can be fast with the gear tucked, it struggles on the up line and must have a great deal of speed entering any looping or vertical maneuver. I stick with energy management type flying when doing any aerobatics.

Conclusion
This plane was intended to be used in Fun Scale events and has proven to be too much of a maintenance hog to be practical. At a local event this weekend, the third tailwheel actuator failed, the left main retract stuck in mid position, and to top it off, the cowl worked its way loose, which then rested on the rockers keeping valves from working correctly, stifling power and resulting in barely getting it back on the ground and putting an early end to the event.

It's a shame because once things do work, it flies like a dream. It now has 18 flights with twice that many take offs, landings, and touch and goes. It truly is a beauty in the air and paired with the Evo, the realism that reminds you of the bigger brother Comp ARF's with the Moki's. Problem is now, I'm back to waiting on gear repairs and missing events with a $4K hangar queen that's not even that pretty anymore. Now I'll probably have to finish the season off flying something else and pondering the sale of the Corsair. The project had so much potential...what a shame.

Herc

camss69

My Feedback: (46)

Great post, thanks! I'm curious, what would you think of the plane if you didn't have the landing gear issues? It seems most of your frustration was with the landing gear. Initial installation of the gear doors sounds like it was a pain, but you mention they haven't needed adjustment yet.

Herc Pilot

My Feedback: (15)

I agree most of the frustration stems from the gear issues. There are some quality issues that can be remedied and overlooked, but should we have to for a plane at this price? There were three of us working on this project, and the gear and doors have consumed probably 1/4 of the total build time and at least 1/2 of the maintenance time to date. Surely a little more attention to the door design/installation and would have made the assembly a much more enjoyable experience. After looking Horizon's plane in Toledo this spring, it appears our install paralleled theirs, but it took much guesswork to get to that point.

My other real let down was that the plane was marketed as a perfect combo for the Evo 77. As a radial lover and having previous experience with the Evo 35cc, it seemed like a natural choice but proved to be only enough if everything is right with no real margin for error. I feel this is a bit misleading and even after careful break in and prop testing were we able to get the plane to perform to a decent standard.

Personally, if I were to do it over again, I would strip it down, glass the outer panels and tail, paint the whole thing, but then we've lost the reason for buying an ARF in the first place. I think it would be more realistic around $799 and paired with some Sierra retracts and a few of the other mods mentioned here. Someone with limited building experince could be in for a surprise if expecting 'pug and play'.

Herc

chorner

I agree with you Herc on most points. The covering especially is terrible... my only "real" regret was that I didn't glass and paint the plane myself. Also... as I've mentioned a few times in previous posts, the Robart gear leaves something to be desired. I complained numerous times to Robart, and at least was supplied with a DIY fix for the tailwheel actuator. I now need to replace the cam follower as they have slowly bent...

Be sure to loctite the screws on the cowl for sure! Two flap servos is also a must... and I decided to leave off the rear gear doors myself, as well as sequencing the doors to pull back up after retraction so there were no clearance issues when landing on grass fields.

As far as the Evolution 7-77, I have found it to have more than enough performance for my needs. However... this is probably to do with the fact that I'm running 16% nitro, 7 % oil and I have converted the engine over to CDI spark ignition. It really woke up the engine, and I now pull around 6,350rpm on a Mejzlik 24x10 which I use for flying. I tuned it back only to about 6,200rpm on the ground, and she runs great and unloads nicely in the air. As mentioned, take-off is 'scale' and the use of flaps help as the gear definitely creates a noticeable amount of drag. You have to land this plane with a good bit of speed for sure until you're comfortable with it, but I've since found the "comfort zone" and am able to land it in very slow and have a pretty short runout. The flaps help a lot, and probably pulling up the gear doors in my configuration removes a bit more drag... but she definitely can drop quick once the power is off.

It's definitely not for everyone and requires some upkeep for sure; so I'd definitely agree with your general conclusion Herc.

camss69

My Feedback: (46)

Herc, what altitude are you at?

Herc Pilot

My Feedback: (15)

chorner,

I would imagine your engine mods are a huge gain. We're running 7.5% nitro, 10% oil, and the rest alcohol. Also, I'm curious.. what was Robart's proposed do it yourself fix for the tailwheel actuator? We ended up fabricating aluminum plates that could be screwed onto the outside of the actuator to hold it together. The new actuator that we had on back-order for months now finally arrived at the LHS yesterday. I guess it's been redesigned and the case is now all aluminum. I don't have much faith that it will last any longer, but am willing to give it a try.

camss69,

Our field is around 800ft ASL.

chorner

Here, the aluminum case is what I had suggested and been on the phone with Robart about since probably March now. I received my replacement with the aluminum housing back in early July as soon as they were finished. I wasn't sure if they had gotten them out to hobby shops yet at this point.

The he case will indeed fix the problem. However, make sure your screws are going in straight through the aluminum housing and not on an angle. I took mine apart as I wanted to check and found that there is very little room for the wire to "gather" in the back of the aluminum case (there is a small groove in there aligned to the centre with the exit hole for the wire) - turns out there wasn't enough electrical tape to provide a shield between the motors +/- terminals to prevent it from potentially shorting out on the case.... If the screws weren't in straight, you may find on extension of the gear it will cause enough force to push the motor a bit further to the back of the case and potentially kill the motor.

I I modded mine by opening up the wire exit hole to a slightly larger diameter and better insulating the wires. It then allowed the motor to sit further back in the case and line up the screws straight. Had a number of flights on it now and 0 issues. The main issue was that the amount out of the motor allowed more torque than the cheap plastic could withstand. The aluminum case will be enough to prevent that as long as the screws are in securely.

excuse typos. Darn iPAd will fix later

bjohnson80

My Feedback: (63)

I have about ten flights on my Corsair now, and I really enjoy it. I went with a good old G62, OEM muffler, 22x10 Mejzlik prop, and an old set of Robart air retracts I had from a Byron corsair. Nothing fancy, but I do use the thin oil that BVM sells for the air system, and no problems so far. I also did gear doors, went with four servos (one on each main door) and used a matchbox. No issues there so far. Each trip to the field I seem to remove a little more nose weight, perhaps the published CG is conservative? Also using just one JR8411 on the flaps, and dont see any problems so far. I got my drop tanks to release the other day, which was cool and the kids at the field loved it!

Herc- sorry to hear about your troubles, but I just wanted to share my experiences. My only real complaint is the covering, ten minutes in the sun and its a mess. But honestly I have never had good luck with dark colors of ultracote.

Brian

njmheli

Hi Guys.

Well,firstly.....Herc,.... welcome to this thread and thanks for a great post with all your information and flight report,very interesting ...

As you know,I have posted quite a bit on what I have been doing with my Corsair build..........must be going in for a year now !!! ( doesn't time fly by,when you having fun !!! ).......

I have had my issues with the Robarts,but as mentioned in my older posts,all sorted now I stripped down each main,when I first had a problem,first thing to replace was the "flimsy Yoke",was replaced with a fully machined ( from steel ) yoke,all screws and bolts were secured and "modified,better "Robart" actuators fitted.......the TW actuator went in the bin,replaced with a D & L actuator , TW spring changed out ( stock one a joke,doesn't compress !!! see photo,that's how it came out of the spring cylinder )...........U/C set up working 100% on all the "bench testing" that I have carried out.........quite alot !!!

My question is : How accurate are the "flying weights" as read in these posts,I only ask this as I appear to have built a very heavy Corsair now and I have some figures,which I'm sure you will all scream horror at !!!!

My build is using the 84R3 ( Ray English modified )........so I have a re-modified F/W and extra supports running along the fuzz crutches ( all posted earlier,with photo's in this thread )......I accept the fact that the D & L TW actuator will and has required me to add extra weight in the nose as it sits well AFT....
My fuel tank ( Ali,but similar in wt to stock item ) is up on the c of g,so not too much of a problem there,pilot...........ok,well he could lose some weight I guess,bomb release as std..........usual servos for gear doors ( non on tail wheel door ),Spektrum Cockpit Rx....etc,etc...............

I'm sure that every thing ( bar modified F/W in some cases ) is a most of you have built in your Corsairs....?

All my 3 main lipo's are way up front,just behind the F/W,U/C + lighting lipos,just on c of g.....total weight is 1.5 Lbs.

I took the plunge and have a Xicoy c of g meter............very easy to use and very,very accurate......( checked against known weights and within 1g !!! )

Now the bad bits...........All up weight is 37.5 Lbs !!!!

This will give me approx 63 ozsqft (193 dm2 ) wing loading and a WCL of 20.4

I will have added approx 2lbs to the F/W ( I never add weight to the cowl )............

Regards..................Nick (UK).

camss69

My Feedback: (46)

Whoa!! 37.5lbs? Is that the number the Xicoy gave you or did you weigh it separately?

camss69

My Feedback: (46)

So has anybody flown it with the 60cc Saito radial yet? I still have not bought my engine, I guess I'm waiting for the perfect solution to come along but so far it hasn't... It's confusing because you read one report that says the Evolution 7-77 is "enough" and the person is happy, then you read the next post and it's not going to be enough. The 60cc looks like it makes less power according to specs than the 7-77. The Saito 84 makes the power but it's a lot of expense by the time you do the RE mods.

I've been slowly working on my Corsair, I went with dual flap servos but I'd be lying if I said I didn't think twice about the additional weight of the second servo. It's all installed and now I'm up to mounting the retracts. I went Sierra trying to avoid the heartache the Robart electric gear are causing people. My last big decision is the engine... I want it to sound like a radial, at a minimum a 4 stroke twin.. The 2-stroke while probably the most sensible choice just isn't the same..

Now I'm thinking save weight and skip the gear doors and all the associated servos, wiring, weight etc... Skip the pilot... But where does that stop... I bought the plane because I wanted the scale details.