I am awaiting a JR Propo V90 Explorer in the mail. I will be using it as a practice plane until I get my 2 meter ready to go in another 2 years or so, given my time to build. Some questions:

1. Any glaring flaws in the design in terms of assembly? By this I mean difficult to access areas where parts need to be placed, super tight installation, etc.

2. What engines are you folks running?

3. How has the overall durability of the airframe been? How many flights does yours have? What have you had to do to keep the airframe sound?

4. Any mods that has greatly improved the airframe/or flying characteristics?

Thanks in advance for your help!
Regards,
GPB

http://www.rcuniverse.com/showthread...hreadid=276870]

Thanks so much for all the usable information!
Regards,
GPB

The guy on Ebay who is selling these would never answer my question: Are the horizontal stab holes pre cut? The picture of the rear of the fuse showed solid covering.

Thanks again,
GPB

I have the fixed gear version and the stab holes are cut and covered over. Just cut the covering out and glue in place. Mine was aligned perfect.
DEG

Glowplugboy
Is yours with retracts (v90 FAI) or fixed gear (V90 ACRO)
I just recevied the FAI version, and would like to communicate with you and anyone else interested in these planes.

My FAI version has the stab cutouts also-you just need to cut away the covering.

I am terribly disappointed with the instructions and lack of information. Also I did not get any graphics. I've been looking for someone that can possibly make me a set. I remember a name of Customcutgraphics but have not located him yet.

I was originally thinking of a OS91FX W/TUNED PIPE but after seing the plane I'm now leaning toward a YS 91 or possibly YS110 when I can get one.

Sorry for the long post, but I was about to post similar questions
Thanks

Eddie

Hi Eddie,
Mine is the one with retracts, but I am anticipating flying it fixed gear. I am considering two different engines: a Magnum 1.20 two stroke or a Magnum .91 FS. Although neither are considered "pattern engines", I believe they will deliver adequote power for this airframe to be a good practice ship until my 2 meter gets finished in the future. Given the long tail moment, I am betting the airframe will need the additional weight of the 1.20 two stroke.
Regarding your dissappointment, I find your experience to be so common with ARF's... there's always something missing, of poor quality, or just plain wrong. These problems take hours to correct and in my opinion, take away any convenience the ARF format is suppoed to offer and replaces it with alot of frustration. I wish I had the time to build like I used to...
In the "good ol' days" of pattern, namely the late 70's to mid-80's, I could get a glass and foam pattern ship from box to runway threshold in about 2 weeks. Ha! Never again!

I agree with you totally.
I think it would be rather sinple to beef up tha bottom of fus for fixed gear. I was /am thinking about that also, but a good friend who flys pattern told me I needed the experience with the retracts. So I haven't decided yet. I'm not sure what gear I'd want to use, and I just thought ,after reading your comment about nose weight, maybe I don't want to move the weight of the gear forward.

I hope to get my unassembled plane weighed this weekend - then I can start looking at location of servos and what motor etc. i'll let you know soon as I get the info.

Installing a 2stroke with a pipe would require some work.
But it wouldn't be too diffcult. Would want to build a pipe tunnel - the plane comes with a bottom hatch.

I'm not happy about the wooden motor mounts but am l looking forward to trying the motor mount. My friend told me the name of the guy that 1st used that type isolation, but I don't remember tha name. I don't even know how to describe the motor mount -when you get your mayeb you can furthert educate me.

I've been arround RC since 1978 but am a NEW participant to pattern - been an admirer from afar for a long time.

Sorry for the long post
Eddie

I am assembling mine now.

Mine came with fixed gear. I would not have purchased it if it had retracts that are a pain.

I am installing a Saito-120. I threw away the soft mount that came with the kit. Then added an extra thickness of 1/4 ply over the wood motor mounts to substitute for the soft motor mounts. The Saito-120 fits the width of the wood mounts just perfect

I think the Saito-120 is just slightly heavier than a YS-91 and probably about the same power.

Brent

It seems the consensus is that the kit supplied motor mounts are not very good. Anyone else have good, bad, experiences?

Eddie,
Sorry about late reply to your PM. Instead of replying to the PM, I will post here.

All the information that I have below are based on Acro Version.

The kit that Yuejin selling at eBay are not from JR. He is getting the kits directly from the Manufacturing company in China, so NO Decals!!

I bought mine from him also. Acro version with fixed gear.
As far as I know, the differences between the Acro & FAI are the control surface sizes.

When Hajime Hatta designed the Explorer about 10 years ago, they were mostly built in Japan with very nice quality of hardware.

I believe they stopped building them in Japan a few years ago and moved the production to China. This company built H9 Mustang 60. Kyosho Giles 60 etc. I checked out the website recently, but could not find the info anymore. There were number of kits that we know as from Japanese companies actually built by this Chinese company.

Most of hardware included in the kit are not very good.
Some of those who have Acro version, have replaced them with MK parts (especially the control horns). Some also replaced the hinges.

Mine (still in Box) has a few spots of woods showing because of poor covering job. Mostly at hinge lines.

Acro version is possible for 3D. I believe it will hover well with YS 110. Maybe with YS 91 also.

The engine mount if they are same in the FAI version. They are similar to the one from MK, DaveBrown, World Model, Go Model, Super Quality Series of Kyosho etc. Out of these mounts, MK & Go Model are from Japan.

I use Go Model mount in my Beat On 90 because the airframe itself was designed for Go Model mount.

If you guys do not like the engine mount, you may change them with MK ones. World model engine mount.

Just be sure they fits right without changing the thrust line.

Brent, if you still have the original mount that came with the Explorer, would you give them to me? I will pay for the postage.

For flying quality, most of people had good results.
Since I have not purchased the FAI version, I do not know exactly how different the two versions are.

Perheps, if someone upload some pictures of FAI version kit, some of us with Acro version can compare them much better.

One guy with Acro version complained the wheels going bad with a few flights.

Acro version's aluminum fixed gear is light enough with only around 110 grams of weight.

I was thinking about Bolly fixed gear, but they are actually heavier.

I replaced Spinner (2.75") with Tru Turn FAI 120slot LB.
The sticker on cowl peels off easily.
I cut my decals with trim-sheet. my Beat On 90 picture has the lettering in blue on both sides.

If you have hard time understanding the instruction, send me a copy, I will try to help explain as much as I can. I know I those Japanese and Chinese do their instructions.
Still the instruciton included in Explorers are at least 1000% better than the one included in my Beat On 90 ARC kit from Pilot.
I did the translation for the Beat On 90 ARC if you need to know.

Hope this helps,

By the way, I forgot to mention above.
Based on the spec, the FAI version is heavier. a light 120 engines will be very good.

GPB,
What do you mean by the engine mounts as BAD?
Is there specific parts that are not good?

Eddie,
Keep the retract. However, Check the quality of retracts, if not good, replace them with better retracts such as MK, Supra (I got several pairs) etc.
Also, check the retract mounting before assembly.

I am one of the long-posting guy, so forgive me if they are not arranged well.

Patternflyer
Thanks for the reply. The info is great.
I am considering the retracts. I have a JR 703 low profile retract servo already. I do worry about the mechanical retracts quality.

I have a OS 108 2stroke that I'd love to use with a pipe but not sure I want to do the surgery to get the header in place . I could easily build a replacement wing pipe tunnel to replace the wing hatch. But then again I'm not sure how to mount a pipe under a 1-piece wing. I know it is done - I've seen pics here on RC Universe but can't imagine the assembly procedure each flying session.

Because of my 2-stroke concerns I'm leaning now to a YS 4stroke. I am in the process of getting a YS91 . Do you think that would not be enough motor or did I missread you post.

Now about the motor mount. I am actually looking forward to trying the included motor mount -the part that bothers me is the wood rails. What is your feeling about them - do they tend to weaken with age. - Is there anything I can do to protect them -other than a good coat of thinned epoxy.

I too tend to be a long poster. Sorry
Eddie

Eddie,

Your post is way shorter than mine. Don't be sorry at all unless you write like me.

I believe the YS 91 should be fine for the plane, just try to minimize the weight. The Acro version weighs around 3500grams (I believe this weight is with a YS 91).
FAI version is heavier around 3600 ~ 3900grams. Not sure how it got heavier.

Both versions have same wing area of 56.1 Sq.dm.
Since the weight of final RTF plane will vary depending on the equipments and engine used, as long as you are under 3900grams, you should be fine.

My Beat On 90 weighs around 4100grams with current heavy wing. (wing weighs 1160 grams). Wing area is 53.0 Sq.dm.
It flys ok with 30% nitro, so Explorer should not be a problem.

For the engine mount rail. How thick is it? I don't remember how thick it was in my Explorer Acro. I also do not have picture of it.
For reference, I am attaching a few pictures of my Beat On engine mount. The rail is 3-ply aircraft plywood under the actual mount. (about 10mm thick)

Additional ply-wood in the front end and rear of the mount for installation of the engine mount.

Let me know if this can help. If not, I will try to take a few more pictures. (My Explorer is behind a whole room full of boxes.)

another picture of mount from the front cooling area of Beat On

PatternFlyer
Thanks for the pics. Iassume you've not had any trouble with the motor mounts or you wouldn;t have 'em on the Beat on :-)

GlowPlugBoy - I don't have any experience with these mounts but it looks good. My local pattern guru said they're good and if Patternflyer is using a very similar mount -hey that's good enough for me. Certainly not gonna pay the price for a hyde mount if before I try these out.

Yousaid you were gonna put fixed gear on your plane. Do you have a particular set of gear in mind. I'm still debateing the retract issue.

thanks Eddie

I was thinking about using the retracts and just locking them in the down position, maybe putting some wheel pants on them. Won't know until I get the kit late this week.

...and I am pleasantly surprised by the overall quality of the design, wood, and construction of the airframe. The covering job alone would take me a month to complete. The hardware is of poor quality, but I expected this and will replace it with what I prefer. I don't think I will be using the engine mounting system, either. Looks really fragile. I will opt for a mounting system, that believe it or not, comes from my combat experience. In order for the engine to be properly centered vertically in the engine compartment, it needs approximately 1/4" spacing off of the ply wood rails. I will create a mounting plate with 1/4" nylon kitchen cutting board. Not only will this give the needed spacing, it should also act as a mild vibration dampener. Also, I am going to mount a Magnum 1.20 XL four stroke in the nose. It will be a little tight with the firewall, but the added umph with very little weight gain over a .91 FS should help the flight performance. :idea:

GPB
Before you make up your mind about the motor mount, Take a look at MK's version and Dave Browns version. They make motor mounts VERY similar and I have heard nothing but top notch praise for all MK and Dave Brown products. If they sell a similar product then I feel confident in trying the inlcuded version. Also my Pattern guru said they are good mounts.

http://www.gatorrc.com/
click link " hi isolation engine mounts under the MK banner on the left

http://www.centralhobbies.com/Engine...davebrown.html

Of course the above is another IMHO type statement.-You do what is right for you. :-)

I too am impressed with the kit quality. I am a little concerned with the smallness of the spar that plugs between both wings. It seems small to me. I'll use plenty of glue amd possibly "glass the joint, just hate to have to peel back covering if I don't need it. What do you think?

When you say the hardware is of poor quality, which parts are you referring to. I am questioning the control horns. Do you think they're any good. As far as the oushrods -that's junk.
Thanks
Eddie

Hi Eddie,
Thanks for the heads up on the mounts, I will take a look at them. I am replacing all hardware: control horns, tail wheel, retract landing gear, main wheels, etc. My time is so valuable, I just have it to have to repair or replace things like this which may or may not stand up to day in, day out flying. Likewise, I am going to replace the wing joiner with some 5 ply plywood and glass the center section. Type to you later.
GPB

Can anyone upload a few pictures of the kit or build FAI version Explorer? I would like to see fron the front to the back end of the wing mounting. Mostly for inside area for engine mounting, gear installation, fueltank etc.
Thanks,

Patternflyer
I'll attempt to post some pics. I'm not sure exactly what you want to see. If these don't show what you need, let me know and I'll reshoot.

Notice the motor mount area and lower chin is already coated with epoxy or something, but mine is done sloppy - areas missed, I'll have to go over it again.
Eddie

Another pic. I have total of 11 pics. If this is anyhting you want I can e-mail them to you & not tie up This board.

Tank area

The servo tray is not glued in place. I just placed it there for the pic.