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Old Aug 12, 2012, 12:18 PM
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Old Aug 12, 2012, 01:11 PM
Tossing planes into the snow
Canada, BC, Smithers
Joined Nov 2011
3,080 Posts
Washout

My understanding of washout is that it's supposed to prevent a tip stall if the AOA gets too high. The idea is that at a high AOA, the wing tips are still flying and providing lift. What about when it is flying at a normal AOA? What is the washout doing for you under normal flying conditions? The Radian has no washout, and presumably has less of a tendency to tip stall than the RP due to the up-turned wingtips. Of all the planes I have, the washout on the RP is the most extreme, and it must have been put there by the developers because they thought it was very necessary.

Two other planes that have often been compared are the Mustang and Corsair. The Mustang has quite a bit of washout and the Corsair has only a tiny bit. The Corsair is an easier plane to fly than the Mustang and has no bad habits. The Mustang was famous for tip stalling, and the washout was put there to reduce that tendency. Could it be (this is just wild speculation on my part) that washout is a "fix" that is needed for some designs and not for others?

This is also of interest for anybody considering doing a decalage adjustment on a RP. If you compare the stabilizer angle with the wing cutout on the fuselage, there is a big difference in angles. As you move out towards the wingtips, that angle disappears. Finding the mean chord line on a wing with severe washout ends up being a judgement call.
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Old Aug 12, 2012, 02:20 PM
Keep Flying
Swedesboro NJ
Joined May 2008
752 Posts
Hey Jovanx and Radio Active

thanks for the reply.i just got back from the field,went over and did a couple more flights,had 2 more great 25 min flights with the cog at 77mm,she was very docile,i could let off the controls and get a drink catch a snack and it was almost like it had rth on it just flew on it own above me just riding the breeze,i was getting more confident so i put her into a couple 45 degree dives to bring her down quick and check it out,no problem full control and pulled right out,i think your right this is not made for a full powered dive,but i still thought it would pull out LOL guess i was dreaming .its a glider not a sport plane,that is a good idea to put a camera looking at the tail to see whats going on,i reinforced the whole back with carbon and it pretty stiff way better than factory,the whole fuse has been reinforce since the crash with carbon going from end to end,and up the rudder and tail,i also added ply to the elevator so thats not flexing.i just think its in the wing design,the way these flex could have some influence on it dont know i not a engineer,its funny what radio said as she was diving and i was trying to pull out i was hitting the flaps and buttons and no response,it was also pretty windy and i am sure that influenced it but as she kept nosing i thought about going inverted and just pushing the stick all the way forward and see if she would come out and i thought this is not a 3der just keep on the elevator and rudder,all that happened in seconds as she was coming down,now i wish i would have tried to pull out inverted,next time LOL hope not.well i am really happy with her now that i have some good flights on her,i am just going to remember to fly her as a glider and not a 3dhs edge,lol its a lot better to see now that its painted the yellow trim really stands out on turns and very easy to make out top from bottom,i might eventually stiffen the wing up a bit but for now i want to enjoy it a bit and not do more full speed dives for a while LOL, time to check out the vids from the last 2 flights

Ron
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Old Aug 12, 2012, 02:24 PM
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Australia, WA, Perth
Joined Jun 2012
69 Posts
Ron, the next thing I do is taping up the slot in the canopy. I have a suspicion that the turbulence, and especially in the wash of the prop, caused by such a slot would be a factor that's impacting the effect of the horizontal stabiliser.

That would also explain the trim problems I had, as I was using a lot of partial throttle on that day. What does a stabiliser do when exposed to turbulent air flow? Maybe even cause a nose dive? Maybe someone can test this in a simulation, any experts here? It goes against the grain to make such a nice streamlined canopy and then cut it open just to make it easier to remove

It's just a hunch but I will tape up that slot anyway. Will take a while to test the outcome as I am waiting for my new propeller to be delivered and I have some busy weeks ahead, but I'll keep you posted.

Tony


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Originally Posted by snoopy3440 View Post
Has anyone given an explanation as to why this goes into a dive and does not come out,i did a search and read many people have had the same thing happen but maybe i missed what the reason was,the 2 times it happened to me i intentionally put it into a steep dive after reading about this happening to others i wanted to experience it for my self and see whats going on,do not want to put all this fpv gear on a plane that is going to self destruct .the first time i did it i was flying slow and i nosed it over and in went into the dive i had no elevator response and i dropped the full flaps and it came out ok the other day when it did not come out,it was blowing pretty good and i was moving along pretty good to keep from being blown all over, so i put it into a pretty fast and steep dive .but nothing more than any other plane i have would have come out of,but she kept going down even after i dropped full flaps,i was was even on the rudder when i saw it was not coming out,i think i hit every button on the radio at that point LOL ,after that crash i did notice the motor mount was not straight ,[not from the crash,motor mount was mounted angled ]and i am using a heavy bat 2200 mah so maybe that had something to do with it,and it was very nose heavy before launch,but nothing extreme,so this morning i am going over the field to try some different cog i centered the motor,adjusted the cog and am using a 1800 mah smaller lighter bat,
but if anyone has any info on why the radian does this i am all ears,it seems a lot of people have had this happen,i just like to know if i am doing something wrong or need something adjusted,i even thought about extending the elevator,i saw this mod on the easystar,

thanks Ron
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Old Aug 12, 2012, 02:35 PM
Tossing planes into the snow
Canada, BC, Smithers
Joined Nov 2011
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Quote:
Originally Posted by scarborofun View Post
It goes against the grain to make such a nice streamlined canopy and then cut it open just to make it easier to remove
The slot is not there to make it easier to open but to bring in some air for cooling of critical components. If you are flying the plane with the motor running it would be better to keep it open. If you are flying it as a glider with short motor runs, it would be safe to tape it up. It will provide some drag that would be of concern to competition pilots, but would not create enough turbulence to affect the stabilizer.
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Old Aug 12, 2012, 02:40 PM
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Old Aug 12, 2012, 02:48 PM
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Australia, WA, Perth
Joined Jun 2012
69 Posts
Canopy slot

Thanks for the tip. That will also explain the slots in the bottom flap, though then battery is blocking most of the airflow. I'll tape it up anyway and see what's happening It's more a glider for me and the motor time is limited.

Tony

Quote:
Originally Posted by Jovanx View Post
The slot is not there to make it easier to open but to bring in some air for cooling of critical components. If you are flying the plane with the motor running it would be better to keep it open. If you are flying it as a glider with short motor runs, it would be safe to tape it up. It will provide some drag that would be of concern to competition pilots, but would not create enough turbulence to affect the stabilizer.
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Old Aug 12, 2012, 06:45 PM
A geriatric flier
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Australia, NSW, Braidwood
Joined Nov 2008
885 Posts
Why a 2200 battery?

Can someone explain to me why one would want to put a battery any bigger then 1300 mAh in a glider like the RP? I sometimes use a 1100 mAh with a bit of lead taped onto it to make it the same weight as a 1300 mAh and after an about 30 sec launch and a few bursts to take the RP up again when I loose lift I can wander about the skies for 20 mins. By then I have lost concentration and bring it down to land. I generally only put about 30% charge back into a 1100 mAh. Surely a 2200 mAh is like flying around dragging an anchor.

By the way "scarborofun" has my old Radian turned up in Perth yet?
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Old Aug 12, 2012, 07:23 PM
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NorCal
Joined Dec 2009
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Quote:
Originally Posted by Watdazit View Post
Can someone explain to me why one would want to put a battery any bigger then 1300 mAh in a glider like the RP? I sometimes use a 1100 mAh with a bit of lead taped onto it to make it the same weight as a 1300 mAh and after an about 30 sec launch and a few bursts to take the RP up again when I loose lift I can wander about the skies for 20 mins. By then I have lost concentration and bring it down to land. I generally only put about 30% charge back into a 1100 mAh. Surely a 2200 mAh is like flying around dragging an anchor.

By the way "scarborofun" has my old Radian turned up in Perth yet?
I can see a big battery if the plane is a photo platform but it seems some people just don't like to fly the plane as intended. It's a glider.
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Old Aug 12, 2012, 07:40 PM
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Australia, WA, Perth
Joined Jun 2012
69 Posts
If I think back 35 years, the receiver, servos and NiCad batteries together with the bits of balancing lead used to weigh about as much as all the bits in an electric glider of today. I still have one of my old Graupner 2.4V servos, it weighs 50 grams. The inbuilt "electric bungee" comes as a bonus, or else the plane would be too light
To your question, I've heard a long retrieving pole has been tested successfully. Not sure who's plane it was and if it had crossed the Nullarbor.

Tony

Quote:
Originally Posted by Watdazit View Post
Can someone explain to me why one would want to put a battery any bigger then 1300 mAh in a glider like the RP? I sometimes use a 1100 mAh with a bit of lead taped onto it to make it the same weight as a 1300 mAh and after an about 30 sec launch and a few bursts to take the RP up again when I loose lift I can wander about the skies for 20 mins. By then I have lost concentration and bring it down to land. I generally only put about 30% charge back into a 1100 mAh. Surely a 2200 mAh is like flying around dragging an anchor.

By the way "scarborofun" has my old Radian turned up in Perth yet?
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Old Aug 12, 2012, 08:56 PM
KAE
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United States, WI, Sheboygan
Joined Jan 2010
219 Posts
Had the maiden flight of my RP this morning. It went well, although I had some issues at first. I had it balanced it out at 70mm per the manual, but it just wanted to keep pitching up. Had to do some trimming to get it flying right. After that it was great. I'll try moving the CG back a bit.
I used Eastcoast78's DX6i setup (I used 40% on the Aile to Rudd Mix though). Didn't try Crow yet. Thank you Eastcoast!
Been lurking here for a while, just wanted to thank you all for everything I've learned so far!
Here's the video:
Radian Pro: Maiden Flight (7 min 49 sec)
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Old Aug 13, 2012, 12:16 AM
Dixie Normious
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Can A da....Ehh!!
Joined May 2010
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Having AIL/rudd mix is a good thing on a lot planes. I still like working the Rudd manually.

As for your CG, try 77mm and position your battery to have the plane want to slight fall to the nose, so a touch of forward cg.
This well help with the Nose up/porpoising!!( go into a stall, fall out, gain air speed, go up into a stall etc...)
to fix this all you need to do is give your elev trim a few clicks down (pushing up on the trim).

You could also trim that stall out, buy giving few clicks of down elev.
What i do set the battery/cg as i mentioned above. Get up and make sure your in the head wind. cut throttle and see what she wants to do!

I would go with trying to trim it out first!
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Old Aug 13, 2012, 12:29 AM
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eroeder's Avatar
United States, TX, Frisco
Joined Jan 2004
993 Posts
Ok,
I know these are dumb questions, but here I go...
I swapped out the nose cone for a BB turbo ( http://www.espritmodel.com/bb-alumin...ropellers.aspx ) and new 10x8 folding props.
1. How tight is enough? I don't want to overtighten, but I did once have a prop shoot off my ME109 once, so I tend to get overly aggressive tightening and once screwed up a collet.

2. Do I use lock tight on the center screw or props?

3. On the nose cone and stock prop, when you power up the motor the blades fly out and then hits a stop so the prop doesn't bend forward any more and the blades lock into position. On the BB nose cone, the blade can fold all the way forward or all the way back.
Is that normal?

Any assistance appreciated.
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Old Aug 13, 2012, 01:09 AM
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NorCal
Joined Dec 2009
1,716 Posts
Don't use loc tite if it is going to contac plastic. The prop will spin in the proper place once the motor turns.
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Old Aug 13, 2012, 01:25 AM
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eroeder's Avatar
United States, TX, Frisco
Joined Jan 2004
993 Posts
Thanks!

I was considering Loc tite for aluminum to aluminum.
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