FOCUS II ARF construction by-the-numbers
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08-20-2004, 10:14 PM
#183
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RE: FOCUS II ARF construction by-the-numbers
Don are you saying that the 2 panels have different incedence?
ORIGINAL: Don Szczur
Flew the airplane last night.
Here is the detail.
Like all the Focus aircraft that I have flown, this one requires two turns of negative incidence in the left wing. That comes out to about an eighth inch. Upright and inverted spin entries and inverted flight were very stable after this change. This incidence change also brough the ailerons back on center.
I noticed a styrofoam sound when bringing the plane back from its second flight. Apon inspection, I found the small dowels that hold the wing retainer screws were loose and when flexing the wing, looked like they were trying to pop out some.
After an hour of poking, bending, looking and pondering. I took a knife to the wing. After pulling the white covering off up to the wing screw. I cut a small V shaped hole and after moving the (very lightweight) foam out of the way, noticed there was about 1/16 inch gap from where the wing tube socket plugs in to the false rib. I poured a few dabs of 5- minute epoxy in there, let it run down along the gap to fill it in order to provide a strong bond. Then ironed the covering back in place. Tonight the plane flew a few more times and the wing is nice and strong with no movement.
How does it fly? I'll tell you after the NATS.
I'll attach a picture if it comes through, with details on the repair.
Don
Flew the airplane last night.
Here is the detail.
Like all the Focus aircraft that I have flown, this one requires two turns of negative incidence in the left wing. That comes out to about an eighth inch. Upright and inverted spin entries and inverted flight were very stable after this change. This incidence change also brough the ailerons back on center.
I noticed a styrofoam sound when bringing the plane back from its second flight. Apon inspection, I found the small dowels that hold the wing retainer screws were loose and when flexing the wing, looked like they were trying to pop out some.
After an hour of poking, bending, looking and pondering. I took a knife to the wing. After pulling the white covering off up to the wing screw. I cut a small V shaped hole and after moving the (very lightweight) foam out of the way, noticed there was about 1/16 inch gap from where the wing tube socket plugs in to the false rib. I poured a few dabs of 5- minute epoxy in there, let it run down along the gap to fill it in order to provide a strong bond. Then ironed the covering back in place. Tonight the plane flew a few more times and the wing is nice and strong with no movement.
How does it fly? I'll tell you after the NATS.
I'll attach a picture if it comes through, with details on the repair.
Don
08-20-2004, 10:22 PM
#184
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RE: FOCUS II ARF construction by-the-numbers
Well finally I’m getting there.
This Sunday I’m planning to break in my Webra.
Hope to fly it soon.
Still need some minor work to be done to get it ready to fly.
So Greg, are you going to get yours done so I can see it fly.
So which one of these 2 FOCUS are going to fly first. Ha .
Danny
This Sunday I’m planning to break in my Webra.
Hope to fly it soon.
Still need some minor work to be done to get it ready to fly.
So Greg, are you going to get yours done so I can see it fly.
So which one of these 2 FOCUS are going to fly first. Ha .
Danny
08-22-2004, 09:19 PM
#185
RE: FOCUS II ARF construction by-the-numbers
Yes, incidence is different and the plane flies exceptionally well. My focus 1 1/2 is exactly the same situation. It flies very well also.
Here is how you check the incidence. Fly with the ailerons trimmed for level flight, cruise speed. Next, cut the thottole, as if to enter a spin. See which way the plane starts to drift. Mine (when entering from right to left) would roll off to the left slightly.
When inverted, do the same. Going right to left with wings level, cut the trottle and add down elevator to keep level, as in approaching a stall entry to spin. Again, it turns in (to the left).
Add negative incidence to the left wing. Then add in right aileron trim to re-trim during cruise speed.
Do the opposite if its turning out.
Thats it.
Don
Here is how you check the incidence. Fly with the ailerons trimmed for level flight, cruise speed. Next, cut the thottole, as if to enter a spin. See which way the plane starts to drift. Mine (when entering from right to left) would roll off to the left slightly.
When inverted, do the same. Going right to left with wings level, cut the trottle and add down elevator to keep level, as in approaching a stall entry to spin. Again, it turns in (to the left).
Add negative incidence to the left wing. Then add in right aileron trim to re-trim during cruise speed.
Do the opposite if its turning out.
Thats it.
Don
09-19-2004, 07:03 PM
#186
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RE: FOCUS II ARF construction by-the-numbers
Hello everyone,
Now my engine is coming @, but now I have an other huge problem.
The Hole stab is fluttering, very baldly. It seam’s like a bird wing when flapping.
Don’t know why…
Everything is looking ok.
There is only a minor play, but everything else is fine.
I’ve even trim-seal the gaps.
When I’ve look at it at the ground, it seems very stiff.
The only thing I could ( We, some other friend’s at my flying field ) think of is that
the elevator push-rod is vibrating and is the cause of this problem.
Anyone else have this problem.[sm=confused.gif]
This is my set-up :
Plane: Focus II
Engine: Webra 160 XP with MC-Carb.
Fuel: Morgan’s Cool-power 10%
Prop: APC 17X12 Pattern
Servo: on the elevator JR 8411 SA
I’m thinking of putting a piece off styro Foam to help reduce the vibration.
Could this be the answer.[sm=confused.gif]
Thanks a lot in advance for the help, Suggestions. It will be greatly appreciated
Danny Koolman,
Now my engine is coming @, but now I have an other huge problem.
The Hole stab is fluttering, very baldly. It seam’s like a bird wing when flapping.
Don’t know why…
Everything is looking ok.
There is only a minor play, but everything else is fine.
I’ve even trim-seal the gaps.
When I’ve look at it at the ground, it seems very stiff.
The only thing I could ( We, some other friend’s at my flying field ) think of is that
the elevator push-rod is vibrating and is the cause of this problem.
Anyone else have this problem.[sm=confused.gif]
This is my set-up :
Plane: Focus II
Engine: Webra 160 XP with MC-Carb.
Fuel: Morgan’s Cool-power 10%
Prop: APC 17X12 Pattern
Servo: on the elevator JR 8411 SA
I’m thinking of putting a piece off styro Foam to help reduce the vibration.
Could this be the answer.[sm=confused.gif]
Thanks a lot in advance for the help, Suggestions. It will be greatly appreciated
Danny Koolman,
09-19-2004, 07:13 PM
#187
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RE: FOCUS II ARF construction by-the-numbers
Mine was fine untill I crashed and repaired the fuselage. Now my stab flutters also. I'm sure it's because I've lost the center support for the pushrod during the crash and I never paid attention untill I noticed the stab fluttering.
09-19-2004, 07:47 PM
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RE: FOCUS II ARF construction by-the-numbers
Hello Jeff-RCU,
I haven’t done that. A center support, or a support some where in the fuselage to help
reduce the vibration.
Could this be the solution …. ???
Thanks in advance for the help suggestions. It will be greatly appreciated
Danny Koolman
I haven’t done that. A center support, or a support some where in the fuselage to help
reduce the vibration.
Could this be the solution …. ???
Thanks in advance for the help suggestions. It will be greatly appreciated
Danny Koolman
09-22-2004, 08:20 PM
#189
RE: FOCUS II ARF construction by-the-numbers
Danny Koolman,
I really wanted to make Aruba but the hurricanes kept me away from my travel agent...
Here is what I did on my elevator. I cut a pieceof one inch wide by about xx(can't remember exactly) long balsa (I used 3/32 balsa). Do the following steps to get the length:
Get a long balsa stick and push it down the inside of the fuselage, from the front section, like where the canopy or belly pan accesses. Push the stick back until it contacts the mid- fuselage bulkhead, then mark it where it comes up to the last bulkhead in the cutout area. Pull out the stick, then measure how far back the bulkhead is *from the outside of the fuselage".
Now, measure the fuselage diameter at this point, subtract about 3/8 inch and you have the length of the one inch wide by xx inch long piece of balsa sheeting.
Next, punch a hole in it about 1/4 inch. Now assuming you mounted your elevator servo close to the centerline of the fuselage (yes the pushrod will move to each side about an eighth inch due to the servo arm rotational) but that is ok.
Put a couple of "dabs" of 5 minute epoxy on each end of the 1 inch wide by xx inch long piece, then slip it over the pushrod, hold the fuselage nose-vertical, and let the piece slowly slide down the pushrod til it makes contact with the mid-fuselage bulkhead.
Now, put the clevis back on the pushrod and connect back up to the servo. Use that long stick again to straighten out the 1 inch wide piece, making sure it contacts the bulkhead on both sides, and let the epoxy cure.
What I found on my FOCUS 1 was that the pushrod would oscillate, causing substantial trim change at high and low throttle settings. With the pushrod brace in place, the issue went away completely.
Not wanting to take any risks, I used the same pushrod re-inforcement on my Focus 1.5 and the Focus II.
Don
I really wanted to make Aruba but the hurricanes kept me away from my travel agent...
Here is what I did on my elevator. I cut a pieceof one inch wide by about xx(can't remember exactly) long balsa (I used 3/32 balsa). Do the following steps to get the length:
Get a long balsa stick and push it down the inside of the fuselage, from the front section, like where the canopy or belly pan accesses. Push the stick back until it contacts the mid- fuselage bulkhead, then mark it where it comes up to the last bulkhead in the cutout area. Pull out the stick, then measure how far back the bulkhead is *from the outside of the fuselage".
Now, measure the fuselage diameter at this point, subtract about 3/8 inch and you have the length of the one inch wide by xx inch long piece of balsa sheeting.
Next, punch a hole in it about 1/4 inch. Now assuming you mounted your elevator servo close to the centerline of the fuselage (yes the pushrod will move to each side about an eighth inch due to the servo arm rotational) but that is ok.
Put a couple of "dabs" of 5 minute epoxy on each end of the 1 inch wide by xx inch long piece, then slip it over the pushrod, hold the fuselage nose-vertical, and let the piece slowly slide down the pushrod til it makes contact with the mid-fuselage bulkhead.
Now, put the clevis back on the pushrod and connect back up to the servo. Use that long stick again to straighten out the 1 inch wide piece, making sure it contacts the bulkhead on both sides, and let the epoxy cure.
What I found on my FOCUS 1 was that the pushrod would oscillate, causing substantial trim change at high and low throttle settings. With the pushrod brace in place, the issue went away completely.
Not wanting to take any risks, I used the same pushrod re-inforcement on my Focus 1.5 and the Focus II.
Don
09-22-2004, 08:40 PM
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RE: FOCUS II ARF construction by-the-numbers
Hello Don Szczur,
No problem, hope you still could come over here.
I have put a peace of foam instead of the Balsa.
Use nearly the exact same tech nick to accomplish it.
Here is the link to the post, there are some pic of the former that I have used and how it turn out.
http://www.rcuniverse.com/forum/m_21...tm.htm#2186527
Thanks for the info, it’s appreciated.
Danny Koolman
No problem, hope you still could come over here.
I have put a peace of foam instead of the Balsa.
Use nearly the exact same tech nick to accomplish it.
Here is the link to the post, there are some pic of the former that I have used and how it turn out.
http://www.rcuniverse.com/forum/m_21...tm.htm#2186527
Thanks for the info, it’s appreciated.
Danny Koolman
10-13-2004, 09:32 PM
#191
RE: FOCUS II ARF construction by-the-numbers
Mike, here are some measurements- another data point for you.
Ailerons low rate 9 degrees up and down. Expo 19 percent. High rate ailerons 11 degrees up and down, expo 26 percent
Elevator low rate 8 degrees up and down, expo 25 percent. Elevator high rate 14 up and 13 down, expo 50 percent.
Rudder low rate 1 inch (measured from the top of the rudder) with 44 percent expo. Rudder high rate 1 3/8 inch, 70 percent expo.
Normal flight is low rate, stall turns, snaps and spins on high rate.
Good Luck,
Don
Ailerons low rate 9 degrees up and down. Expo 19 percent. High rate ailerons 11 degrees up and down, expo 26 percent
Elevator low rate 8 degrees up and down, expo 25 percent. Elevator high rate 14 up and 13 down, expo 50 percent.
Rudder low rate 1 inch (measured from the top of the rudder) with 44 percent expo. Rudder high rate 1 3/8 inch, 70 percent expo.
Normal flight is low rate, stall turns, snaps and spins on high rate.
Good Luck,
Don
10-13-2004, 09:47 PM
#192
RE: FOCUS II ARF construction by-the-numbers
One more quick comment about the Central Hobbies-supplied pushrod for the Focus II. During the hot summer and cool mornings experienced this last July and August, I was very pleased to find out that trim changes were only 1 to 5 beeps (at 1% trim resolution on the 10X). This compares to as many as 24 beeps on the Focus 1 1/2 (Black fiberglass pushrods). If you can imagine going beep, beep, beep, beep,... 22 times during the procedure turn and free pass in front of the judges... It was a distraction (but not too much since I won the NATS while doing this, hmmm.)
Any case, the CF pushrods supplied with the Focus II have worked very well.
Don
Any case, the CF pushrods supplied with the Focus II have worked very well.
Don
10-14-2004, 10:26 PM
#193
RE: FOCUS II ARF construction by-the-numbers
Make that 7 beeps of down elevator- just flew it today and it took 7, but the last time I flew it was August (warmer weather than the NVRC pattern competition back in late August). Guess its still better than 15 to 22 beeps from cold to warm (or cool to hot) weather from the fiberglass pushrods.
What else? Differential on the ailerons. That's something new. I'm really not that great of a pilot to tell what differential this plane needs. I don't think I have any in (at least not intentionally). I may experiment with this some over the next month or two.
Best of luck with yours,
Don
What else? Differential on the ailerons. That's something new. I'm really not that great of a pilot to tell what differential this plane needs. I don't think I have any in (at least not intentionally). I may experiment with this some over the next month or two.
Best of luck with yours,
Don
10-28-2004, 09:10 PM
#194
RE: FOCUS II ARF construction by-the-numbers
A few additional follow-on items with regard to the FOCUS II.
Lee Davis pointed out something this last weekend which hit me with the obvious. My white landing gear for the FOCUS was slightly off (wheel pants did not face exactly forward). What I did was take a file and file a flat spot on the outside face of each gear leg to make the wheel pant align. What Lee suggested was simply take a heat gun and heat up the gear leg strut to twist the strut and make the wheel pants point straight ahead. Wow, what a great (and simple) idea.
Another thing tonight. It was calm and I decided to do some trimming of the plane. It needed a little more mix (down elevator with low throttle) for down lines. No surprise, as the elevator pushrod and linkages are probably starting to wear.
I did some extended knife edge flight and noticed that the plane was rolling slightly left with right rudder, and pulling slightly to the canopy with left rudder. No problem, I'll just update the mix controls. Guess what! I went to check what I had for mix (Rudder to aileron and elevator, code for the 10X) and there was no mix! This is the first plane I have flown that I did not have any mix in for knife edge. It was close, but not perfect. I put about 6 percent mix for each and now it tracks straight knife edge for extended periods (length of box). Another item of interest. I only have enough rudder deflection on low rate to just hold knife edge- no more. I go to high rate for stall turns, snaps, and spins (as well as rolling loops, one roll circles, and the humpty bump from the top with 2 of 4 down- for extra elevator thow during that radius).
Well, thats it (again, for now).
Cheers,
Don Szczur
Lee Davis pointed out something this last weekend which hit me with the obvious. My white landing gear for the FOCUS was slightly off (wheel pants did not face exactly forward). What I did was take a file and file a flat spot on the outside face of each gear leg to make the wheel pant align. What Lee suggested was simply take a heat gun and heat up the gear leg strut to twist the strut and make the wheel pants point straight ahead. Wow, what a great (and simple) idea.
Another thing tonight. It was calm and I decided to do some trimming of the plane. It needed a little more mix (down elevator with low throttle) for down lines. No surprise, as the elevator pushrod and linkages are probably starting to wear.
I did some extended knife edge flight and noticed that the plane was rolling slightly left with right rudder, and pulling slightly to the canopy with left rudder. No problem, I'll just update the mix controls. Guess what! I went to check what I had for mix (Rudder to aileron and elevator, code for the 10X) and there was no mix! This is the first plane I have flown that I did not have any mix in for knife edge. It was close, but not perfect. I put about 6 percent mix for each and now it tracks straight knife edge for extended periods (length of box). Another item of interest. I only have enough rudder deflection on low rate to just hold knife edge- no more. I go to high rate for stall turns, snaps, and spins (as well as rolling loops, one roll circles, and the humpty bump from the top with 2 of 4 down- for extra elevator thow during that radius).
Well, thats it (again, for now).
Cheers,
Don Szczur
10-28-2004, 09:24 PM
#195
RE: FOCUS II ARF construction by-the-numbers
Control rates for the Focus II that I have measured:
Ailerons low rate 9 degrees up and down. Expo 19 percent. High rate ailerons 11 degrees up and down, expo 26 percent
Elevator low rate 8 degrees up and down, expo 25 percent. Elevator high rate 14 up and 13 down, expo 50 percent.
Rudder low rate 1 inch (measured from the top of the rudder) with 44 percent expo. Rudder high rate 1 3/8 inch, 70 percent expo.
Normal flight is low rate, stall turns, snaps and spins on high rate.
Ailerons low rate 9 degrees up and down. Expo 19 percent. High rate ailerons 11 degrees up and down, expo 26 percent
Elevator low rate 8 degrees up and down, expo 25 percent. Elevator high rate 14 up and 13 down, expo 50 percent.
Rudder low rate 1 inch (measured from the top of the rudder) with 44 percent expo. Rudder high rate 1 3/8 inch, 70 percent expo.
Normal flight is low rate, stall turns, snaps and spins on high rate.
01-28-2005, 10:12 PM
#196
RE: FOCUS II ARF construction by-the-numbers
There is a sale on Focus ARCs. for Piedmont, The ARFs are sold out and the ARC's are on sale for $525. If my memory serves me correctly. I've had a very positive experience with the FOCUS design.
One last trimming characteristic I found is the positive snap to the right is less efficient than a positive snap to the left. I have tried increasing the right rudder throw to see if that will do the trick... once the weather clears enough and the temperature rises enough for flying to continue.
Don
One last trimming characteristic I found is the positive snap to the right is less efficient than a positive snap to the left. I have tried increasing the right rudder throw to see if that will do the trick... once the weather clears enough and the temperature rises enough for flying to continue.
Don
03-09-2005, 01:11 PM
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RE: FOCUS II ARF construction by-the-numbers
I recieved a bunch of e-mails asking about the FOCUS-II no longer being available from PIEDMONT Models. The message is a bit crossed over with the Temptation discontinuation.
THE FOCUS-II IS STILL AVAILABLE.
In fact I believe that they will be bringing in more, which is good news for people needing one or spare parts.
Regards,
Eric.
THE FOCUS-II IS STILL AVAILABLE.
In fact I believe that they will be bringing in more, which is good news for people needing one or spare parts.
Regards,
Eric.