Eric.Henderson

Erik,
Brilliant color schemes - Great photo.

I mix my drugs :-)

Eric.

PeterP

Hi Eric,


Could you please give me a flight performance comparison between the IMPACT and the Pinnacle. You can PM me on this one if you wish.


Regards,

Peter

Eric.Henderson

Peter,
No problem doing it in the RCU forum. I paid good money for these planes so that I can say good or bad things with no fear :-)

They flew pretty close. Admittedly I need more time on both of them. One has an OS 1.60 FI and the other (the IMPACT), has the OS 1.60 w/mix carb, so they throttle just a little bit differently.

First of all the bigger contrast was between the TEMPTATION and these two planes. Everything is slower with a big old wide-body.

They both rolled with very similar input needs. Very little rudder etc. I already had more down than up aileron in the IMPACT so the need for differential did not show up. They both might need a tad of negative diff. as I get more fussy and familiar.

The snaps were close with the edge going to the PINNACLE in the down-line negative snap. They both rudder/elevator spin in both directions. The break was stronger on the PINNACLE.

The down line was slower with the fatter PINNACLE. The up line speed was about the same.

Knife-edge is with either is almost too easy. Doing the 4 of 8 on a 45 and the 4 pt was equal.

My current plan is to compete with the IMPACT's and practice and prepare for the Nat's with the PINNACL. They are that close in performance in my hands.

Sorry I could not differentiate them any better. If I had the sheckles to buy another plane I would get a PINNACLE because I could have it in the air in less than a week of evenings.

Regards,

Eric.

PeterP

Thanks Eric,

The comparison is interesting indeed. Good luck with the practise.


Regards,

Peter

Neo02

Claude,

the Cocaine IS an Impact, i.e. it was reportedly designed from the same people although the factory (and name) changes. Only difference I saw on the Impact is a slightly wider front part.

Regards,
-Fabrizio

pfloyd

Fabrizio, the Cocaine is NOT an Impact! The Cocaine is a Revolution Pro (molds made from the same masters). The Impact is a modified Revolution Pro.

flyinrazrback

My Feedback: (69)

Does the impact have a painted canopy, or are you having to paint them? I am referring to the red, white, blue, standard impact. I am thinking on getting an impact if I can find a builder in TX to build it.

Neo02

Hi "pfloyd",
I politely disagree: Impact, Revolution, RevPro and Cocaine are "to 95% the same model". This statement comes from one who knows: Peter Wessels, german F3A champion in the past, on this forum: [link=http://www.rc-network.de/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic&f=60&t=000319&p=]RC-Network[/link], post #2 (sorry it's in german.
Of course they are not 100% the same, some details change from plane to plane, but I can definitely see some similarities.

Regards,
-Fabrizio

papaone

Hi
Congratulation to Eric for buildind the impact, it's a very great job.
I just want to say there are anothers prebuilt kits (may be F3aLorenz planes are not distributed in USA).
The two planes are alike but there are some differences. The principal are : For the Impact, drawing is straight, underbelly is small, canopy is painted. For Cocaine, drawing is all in curves, underbelly is long and canopy is transparent.
I saw theses patterns in reality and my previous spot was to say that the difference is in relation with buildind and finish (prices are differents also, Impact is cheaper).
For Cocaine or Rhapsody , wing's tube, carbon tubes of the stab are fitted. It's very easy to make it. The alignment wings/stab, the incidences of wings and stab are perfected. It is not made with Impact.
For cocaine there are many designs (thus showed in website and others proposed by Lorenz).
The flights of theses two planes are very excellent (the different results from the pilot).

Claude

JRW

Hi Guys - Rudder / fludder question. In comparison to the PL and ZN kits I've built and flown, the Impact fuselage is much stiffer. The PL/ZN stuff as you know has the kevlar fibers aft of the wing area and to the tail, where as the Impact has the TAVs construction. The PL and ZN kits have one horizontal and one vertical support in the aft section, just as the IMPACT has now been corrected to incorporate due to the rudder/fludder problems.

I'm about to add this new vertical former and horizontal piece as the CARF drawings depict. My observation is that if the much more flexible PL/ZN stuff have basically this same stab supports, then it should be more than adequate on the Impact give that the fuse starts off much stiffer than the PL/ZN stuff. Thus, why are so many adding full tail-moment supports? Does the TAV construction react differently than the Kevlar PL/ZN fuses? I'm going electric and need to come in on the lighter side of construction.

My rudder weight is 66 grams.
Thanks,
Jim W.

byoung466

My Feedback: (16)

There is an explanation here:

http://www.composite-arf.co.uk/announce.htm

I added the crutch from depron to mine, w/ some 1/16 balsa laminated on, maybe weighted a couple oz's.
Necessary, hard to tell.

pbrantuas

My Feedback: (3)

Hi Jim,

For whatever this is worth, I've been flying my electric Impact for about 5 months now and have not experienced any fluttering problem with the original stock setup. I don't know if there is anyone out there that has experienced a flutter problem with an electric Impact, but I would expect that the chances of this happening are a lot less than with a glow setup, due to less vibration through the fuselage, and slower cruising speeds.
I have been contemplating adding a horizontal piece similar to the radio equipment tray to the tail for additional stiffness.

KeithB

My Feedback: (1)

To Brian Y., Eric H., and anyone else that's replaced the leading edge of their Impact rudder,

I've replaced my rudder leading edge using 3/8" balsa so I could get enough of a bevel to have adequate rudder throw, however, using this thick of a leading edge causes the counter balance to not line up with the front of the fin.

How did you guys get 1) enough rudder throw and 2) have the counter balance still line up?

Thanks,
Keith Black

Andy P.

Hi Guy's,

Firstly, I built my Impact during the last few month's of last year. The build was finished a few day's before Xmas day ( Great excuse to get out of the house.........Right! ). Needless to say the first proper tank of fuel was put through the model, in the air!
I should point out at this stage, that the revised/update vertical former which was included in the latest (at that time) instruction manual, had been fitted. However after landing on the second flight, I noticed a vertical crease running from the top seam to the bottom seam on the right hand side (viewed from the rear) of the fuselage but around 4" (100mm) in front of the vertical fin base former (everyone still with me?). After contacting CARF via e-mail, they replied by saying that I had experienced rudder flutter which could have been caused by loose pull/pull cables or the hinges coming loose. After checking both of these items and subsequently ruling them out, I replied with my findings to be told yet again that there must have been a failiure of some kind [&o]. I started to give more and more thought to the issue as to what could have caused the flutter in the first place. Fortunately for me there are members in our club with much more knowledge on this issue than myself so went digging for answers. I firstly spoke to one member who also flies fullsize and thankfully he agreed to look over the model for me, he agreed that there wasn't any slop in the closed loop system & that the hinges were still very much in place. Next, he commented on the fuselage aft of the wing t/e by saying "wheres the support for the fuselage?" there really needs to be a horizontal ladder type arrangement through it's length to support all the side loads exerted on the fuselage in flight, not to mention the slightly compressive nature of a traditional pull/pull cable system, things started to make sense. He then explained that the combination of the engine pulse, no aft fuselage support, compressive qualities of the closed loop and flight loads/speeds etc, could actually induce the flutter effect on the rudder, which may have started what's (rightl or wrongly) described as "panting". "Panting" has been described to me as like a rippling/wave effect travelling down each side of the fuselage until it finds a weak spot and in my case was as perivously described. I also spent many many hours in discussion with another close friend/fellow member of our club over the issue of flutter in general and realised that it it one of the most discussed issues in the aviation world and has been debated and played around with for years. Another major contender for the title of "Best possible cause" is the component weight for each moving surface, ideally the moving surfaces should at least balance on the hinge line also the hinge line arrangement can actually induce the effect as well. As I had now gathered quite a large amount of information on the subject, I decided to e-mail my findings to CARF and suggested the horizontal ladder down the length of the fuse to which they replied by saying that they would assemble another kit and fly it against their factory original during a reps meeting in the following weeks. Anyway, time passed and they eventually replied by saying that neither airframes showed any problems so therefore my claims/ideas were inconclusive. So much to my surprise, I realise that they have announced the "problem" on thier web site and have stated that the ultimate fix for the problem is guess what, a horizontal fuselage former! What a shocker [X(]. This is an EXTREMELY shortened version of the complete scenario, which did include heated exchanges between myself and a major player at their factory. My experience of their customer service is one I wouldn't like to wish on anyone, oh yes I did receive an offer of a discount on a new fuselage but have decided to decline and fix my fuselage.
Anyway, fixes are all done which include:- Horizontal balsa ladder down fuse, removed l/e from rudder and replaced with a conventional bevel edge, 5 hinge pins instead of 4, 45 degree fin brace extending to the stern post and notched in. I built a replacement rudder from basla and sheeted then covered but it came out heavier than the original [&o] so decide to run with the stock rudder and no ballast in the front mass balancer. Had two fantastic flight with it today, which included snap rolls for the first time! Still in tact .
My fellow club members shot some video of it today so hopefully I'll be able to upload it for you soon...................................watch this space!
One mans experience!?

Regards

Andy.

BrianB

My Feedback: (2)

Andy, I feel your pain. Glad you were able to repair it. It amazes me that they still insist there is no problem with the design. Care must be taken when building this plane to insure it won't fly apart. I am on my second one and in the end, it sure flys nice.

Andy P.

Hi Brian/Keith,

Brian, thanks for the sentiment. When I first made contact with CARF I asked them to place an announcement on their website to let their customers know of the possibility of failiure, in the interest of SAFETY. I'm only thankfull for the fact that they have now done that, take a bow CARF, your product has just got better!

Keith, when I replaced the l/e of my rudder I found the same problem, too far back.......right!
I just kept planing back the new rudder facing edge until the forward mass balancer was exactly in line and then bevelled the edges back to the rudder side skins, place some masking tape exactly down the composite side edge first to avoid damaging the surface whilst final sanding back. The bevel dosen't look very deep but I can confirm that their will be enough movement to do the schedules and more.....................

Hope this helps a little,

Regards,

Andy.

JRW

Thank guys for the posts. I think I'll switch my rudder hinges to the traditional type.

In regard to the Ailerons servos. I decided to open up the already relieved slot in the wing toward the servo rib. This made a perfect rectangular hole for the 9151 servo. I then made some 3/8" x 3/8" x 1.125" bass wood pieces, and glued underneath the wing skin (where the servo screws would be), and butted this against the original servo rib. Using a $11 "hot-knife" from Tower, cutting the servo holes couldn't be easier or for me, more accurate. I also did a similar installation on the elevator servos. Now, both the elevator and aileron servos are vertically mounted, easy to install, and line-up correctly for the stock control surface horn placement.

In a trial fit, the metal sullivan 4-40 clevis' fit in perfect to the phenolic horns, with seemingly no slop.

You may have already figured this out, but for those of us who are "rudder-cable-hole-exit-location-impared", an easy way is to think of it like this. The rudder horn hole-to-hole width is 2-5/16". If I match the rudder servo horn dimension to this 2-5/16" width, and mount the servo on the center of the fuselage, then the cable should exit the fuselage where it too is 2-5/16" in width. To find this, just glue a 2-5/16" piece of balsa to a long stringer, and stick it down the fuselage until it rubs on both sides. This at least takes care of the "x" dimension.
Jim W.

Eric.Henderson

Jim,
I might just do this on my second one. The holes in the rib on my first one forced me to fit a new ply plate (actually two plates), for the servo screws. There was no grip for mine at all. I might just as well have done that with a horizontal plate the same as you did.

With 5 more flights in better weather the trims are settled down. The rudder is at neutral. The elevator is close to neutral. The ailerons carry a degree or so each of left trim. I would have to adust the fixed anti-rotation pins to get rid of it.

The up and down lines have no roll. The KE is still sweet. The pterodactyl-screech of the ailerons only happens in the snap and is acceptable.

The rudder is very strong and I use very little for roll corrections etc. It has no problem in cross-winds. The switch to conventional hinging does mess up the clearances with eth elevator halves, so be prepared to sand them away to avoid fouling the rudder. If you have not fitted your elvator-tubes yet then move them forward about 3/8".

I am considering going to four wing bolts fore and aft instead of two in the center. My Pinnacle uses four and it is drum tight. The Impact rubs away at the fuselage sides at the front. With four root-bolts I could make my wings semi-adjustable. :-)

Also the supplied yellow bottom of the wing is as good as invisible in the air. Add something dark :-)

Regards,

Eric.

ERichard

Jim,
Another way that I have found a bit easier is to use a woodworkers caliper and adjust it to match the rudder horn hole-to-hole distance. Slide this up the rear fuse until it touches. To get the vertical alignment, line up a straight edge on the outside of the fuse from the rudder horn to the servo horn location and lightly mark a line (erasable pen) at the caliper point.....No fusing with long sticks down the fuse. Also remeber that this hole-to-hole dimension gives you the forward most point of the cable slot...because rudder deflection will decrease the cable separation the slot will need to be cut from this mark aft.
I've played around with making a rudder "pulley" system for large IMAC birds......These were custom machined, but I have heard people using available pylon racer wheels with great success. I may try this type of set-up on my Impact......nice thing with these is cable is always tight and no cosine shrinking in the cable separation, so the exit slot can indeed be very small.

-Erik

P.S. I was born and raised in Lancaster CA... I was president of the AV Tailwinds back in 1982. Flew mostly at the lake-bed back then before MMM came along. Flew EU-1A's with Jerry B. back then in the "rocket pattern days"....say hi to the gang for me. (Although I think I read in the K-Factor that you are now in Florida?)

ERichard

Just FYI in case there is confusion...here's what I mean by a "woodworkers' caliper"...Technically an outside spring cailper

Eric.Henderson

I agree with Erik on the rudder cable. It is beneficial to have a small "waist" in the two wires. The gap does get narrower when the rudder is deflected. Another effect is the dampening effect at neutral. Just touching the wires or pulling them slightly together deals with "guitar-string effect" or more accurately stated the sympathetic harmonics.

Regards,

Eric.

JRW

Hi Eric,

Nice history about Lancaster. I too know Jerry, and probably some of the other original members there. Jerry gave me a lot of help when I was getting started in early 2000, and gain when I moved back in 2002-2004.5.

Regarding the rudder hinging, I decided to cut off the round edge and replaced with a plate of 1/4" soft balsa, then carved into the triangular shape. I took another soft piece of 1/4" balsa, and made a new rudder post to sit on top of the already glued in original post (didn't want to remove due to its interaction with the stab mounts, and high strength of this area. This second plate basiclly lined up with the aft most edge of the vertical fin line. Now, the tip of the rudder counter-balance is in the correct position. There appears to be enough rudder throw, will finish the "easy-hinge" - ing tonight.

Also, the instructions call for mouting the stock rudder hinges (robart), so that the hinge point is directly against the vertical member of the rudder. Also, calls out having a 4 mm gap between the round LE of the rudder and the original rudder post. Having the platic robart hinges sticking out this far from the actual rudder post "can't" be a good thing. In this fashion, all forces acting on the rudder must travel through these 4 exposed peg-sections of the Robart hinges into the rudder post. Anyway, I'm glad I switched it around.

Jim W.

ERichard

Jim,
You are absolutely right about the Robart hinge installation...I think you will be very happy with your improved setup. You stated earlier that your rudder was 66 grams, I'm curious what your final mass will be after your mods. My main concern with the Impact stock rudder is that there is quite a bit of mass aft of the hinge line. From a flutter point of view, as you know, you'd like to keep most of the rudder mass close to the hinge line....you probably don't want to add more weight to the hinge post area (or add weight to the counter balance to statically balance the rudder...things will indeed get heavy in a hurry).

Originally, I was going to do just what you (and others) have done, but in the end decided to make a completely new all built-up rudder. However, I think that by eliminating the awkward/sloppy Robart hinge installation you have cured most of the problems. Keep us informed of your progress. Maybe I missed it in your earlier posts but are you going Electric or Glow with your Impact? If glow, what engine? I'm still undecided about whether to use my 140 Dingo or 140 RX

-Erik

Eric.Henderson

On my second IMPACT I will put a bevel on the rudder and on the fin. This will allow the rudder to swing without "displacing" as far as number one does with only a rudder bevel.

I flew my IMPACT 8 times today. I tried as many tests as I could think of. There are still no mixes in any fields in code 64 - (just for you JR fans out there).


I managed a few FAI rounds and a partial 2005 masters. Seems to like it all.

Regards,

Eric.

Vortec

What do you think makes the screech in snaps?As my Adrenaline does the same thing in snaps and any other fast aileron movment manouver.

I first heard that when a felow competor brought along his Impact and loved the sound of it.What makes it and is it bad in any way?