HK Firenza

[Erfolg]

The build is nearing completion.

I may need to do some more airframe work. I will not know until I get my Lipo and that could be some time due to a cock up by me.

My concern centres about achieving the CG without ballast.

I have seen and read on another forum about the useless nature of the supplied decals. Well, in my opinion, these comments have some basis. There are two issues, the first the decals were peeling from the backing sheet, leading to the decal being stuck to itself and much more. The second which is a little surprising. The Decal appears to be made from two carrier layers. The lower layer has the adhesive attached to it, the second carries the pigment on its under surface, without any apparent adhesive. The adhesive does not want to stay stuck to the EPO, although initial adhesion seems fine, later it peels of around the edge, curling up. In rubbing the decal onto the model, then causes the upper layer to separate from the lower. Tips from this site had me using UHU POR and canopy glue. Canopy glue does work, although it takes much longer to dry and needs to be held down. Por is much quicker, but here a sticky residue from squeeze out leaves a rubbery line.

A passing comment, the model is far to big for my car, a medium sized saloon, without the wings being removed, The model is designed I think for permanent wing installation. This means I will have to give some consideration to a modification to permit partial dismantling. I can guess that there will be some loss of structural integrity as a consequence.

[Erfolg]

It may seem I have stopped on this model, well you would be just about correct.

I am now in the position of waiting for a Lipo and propeller for the model.

Unfortunately this issue is one of my own creation, on two accounts. The first is that the Lipo was ordered late and the other issue I have ordered propellers on back order. I must say i do feel quite bad about this, as it reflects very bad planning. I cannot even say there are any mitigating circumstances. Just total incompetence.

Now I have the model, it is a little larger than i personally like and HK do a model the Accipetor? which is a better fit for my wants, other than it is probably polystyrene and not in the UK (at present).

I have set the Tx, Rx and servo throws have been set up.

So, it could be some time until this model flies!

 

Edited By Erfolg on 01/06/2013 14:10:53

[Martian]

Tut Tut Erfolg it's just not good enough lol

it will fly when it's ready only you are suffering for it not being airbourne.. the Accipetor looks very similar except smaller like it's little brother or sister. and cheap to if it's in your country

[Erfolg]

The missing bits have arrived. That means that the model can be quickly completed, that right isn't it!

As with most things , it has not gone that smoothly and I am still not there.

But here is the present position.

The instructions do not give any guidance or suggestions as to where the the ESC should go. There being to very obvious locations. I tried both, neither wer imediatly the solution. That being in part due to both the ESC and Lipo having exceptionally short pwere laeds.

 

As can be seen ther are two obvious routes for the power leads, the first through a hole behind the motor mounting. The second was via a tunnel,. This tunnel was finaly used.

The ESC being inseted in a tunnel potentially providing some ventillation. Although no access is available to acess how hot it is getting.

To enable the whole lot to be balnced at the dsignated position 35grams of lead have been added.

A power extension lead is required for the following reason.

As can be seen the Lipo lead can only just reach the Lipo bay.

With Lipo

More work is now required to locate and secure the lipo in the designated bay. This area seems not to be thought out as well as the rest.

I have now done a watts check, everything is well in hand, 37 amps, with a 60 amp ESC. watts drawn 548w. The revs are a bit low @ 6340 rev/min on a 11*6 APC(E) pattern.

Unfortunately I do have some vibration which i presume is the spinner as the propeller has been balanced. So more work is now required prior to flight.

Edited By Erfolg on 18/06/2013 16:28:08

[Mart49]

Erfolg, I do enjoy your commentry, even though I may not reply often! I have also discovered that the "office" arrangements need things like battery extension leads etc to make it all fit, and I'm relieved to see it not just me that has problems On the other hand, it does help in knowing what to do next time!

I'm looking forward to the maiden!

Mart

[Erfolg]

It has now flown, on Friday.

The suggestion that the model is prone to tip stalling could be misplaced. How can I say such a thing, I bet you are asking.

Well the flight did not go completely to plan.

Much of what happened is not that unusual with my models.The model initially had a marked tendency to turn to the left. It also needed a slight amount of up elevator, to avoid the ground. Most commentators talk of a few clicks of up down etc. In my case there was an awful lot of button pushing, before I had the model going more or less straight and level. Even with retrospect, a whole lot less hairy than many models I have flown out of trim. I think it is the large size (to me) that accounts for this.

Things went wrong when i attempted a loop. Only about half a loop was achieved before the model squirreled out to the side. This is when i knew I had an issue. The model was again doing what it wanted, but now strongly attempting to climb. I pushed a whole lot of down elevator, and it kept on climbing. I then decided that a little less power, should get it nearer the ground. This worked in that the model started to sink, nose high. Now the wings were violently rocking side to side, which I was attempting to bring it both nearer and lower, using throttle and ailerons. I did get nearer, and lower, although the violence of the wing rocking did not diminish. At some point I decided to cut the throttle, and the model then dived in, nose first.

All the time receiving advice with respect as what to do from some club members.

Reaching the model revealed the model was and is in one piece. Checking my trousers was also indicative of a successful emergency management policy. But perhaps luck had much to do with the outcome.

The other thing apparent, was that the elevator was at full up. Waggling the sticks, high lighted that the servo arm was stuck in the position it had reached, but wanted to go further, being restrained by the linkage geometry. Though still apparently working.

I am reasonably sure that the wing was either stalled or near to the stall, at least in part. There was none of the nasty wing dropping i have experienced with some models.

I have just come out of my model room, having changed out the servo, for another. It seems OK. I also undertook a few minor mods, about getting the wing pegs, in and out. Changing the servo in and out, took quite a bit of time due the location and the hardware and geometries.

I have not run up the motor again yet and at present hopeful that the shaft is OK. I will try this on Monday, in the garden, as for me this is rather to powerful to run fully, in the house.

I think I can say that the model has to date shown that it is not the beast some have suggested. The size of it makes seeing it much easier than small models, in practical terms that you can go some distance away, without breaking out into a sweat. So to date the model seems fine for club numpties.

 

Edited By Erfolg on 23/06/2013 16:45:29

Edited By Erfolg on 23/06/2013 16:47:26

[Tom Wright 2]

Erfolg.

Did you do a glide trim test ? I sounds like elevator trim was fighting motor thrust line .

Tom.

[Erfolg]

Tom

The problem is servo related (elevator), the track contact seems to have found a new centre, which is at the extreme end of the track. Hmm, strangely it must be something else, as it would not come back via the Tx command. On the bench, it seems fine, though I do not think it is, at least under some circumstance..

The model is far to heavy for the old RC glide test (I was really young then), I doubt if it has much glide.

Its this thing

Edited By Erfolg on 23/06/2013 17:50:56

[pete taylor]

I think Tom was referring to a glide test from powered flight by means of cutting the throttle
This way you can see that if the model dives then the motor was pulling it upwards against the elevator trim, not having enough down thrust built in. Conversely, if the model climbs when the power is cut the motor is doing the opposite and has too much down thrust.
Simple really, but a bugger to do from a hand toss over long grass!!!

[Tim Mackey]

For no apparant reason, other than my name being called out, I have "won" one of these models at the greenacres weekend fly-in. I have ordered some gear for it, but not sure when or if it will ever reach the top of my large "to do" list.

I am planning on using this motor, on either a 12 x 7 or perhaps 11 X 8 prop, and 4s Lipo.

[Erfolg]

Pete, the model did trim out. I think you are not recognising that I am not one of your hot shot flyers.

To trim out properly I will need a lot more flights, that is when I am doing it. Yes you could be correct, in that the thrust lines are not yet correct. This would suggest that the kit mounting is not ideal.

I was extremely lucky that the full up elevator did not lead to the end of the model.

What it perhaps has indicated that tip stalling that has been reported, has more to do with the use of massive motor and battery combinations, rather than a fundamental fault with the kit. Initial indications suggest that using the recommended set up, the model is benign.

Tim

Looking at the motor you have acquired, it will probably be well suited to a Firenza or something similar. I think I am using a 12 *6 as that was the coarsest pitch that was listed on the site from where I bought the APC style propeller.

In my case I am a long way off the motor max or Lipo rating.

[Erfolg]

I have replaced the servo with an identical model.

The model was taken to club No2 and the model flown of the ground. Five minutes of circuits made, then landed.

During the whole of the flight the model behaved impeccably, it took itself off, coped with a 10-15 mph wind, with no issues at all, going where pointed and then landed itself. All with great aplomb.

However I did not do any loops, bunts, inverted flight at all.

On reflection, I still have some concern that the issue is a linkage issue rather than servo. That is because the model was flying Ok on the first flight, once trimmed out. That is until i pulled a loop, where upon the elevator stuck up. The linkage concern revolves around the linkages to the back end being plastic tube outers, with solid wire inners. Although these do seem to work well on small electric models, the stiffness may be an issue with larger models. Then again it could be just my prejudices with respect to these wire type systems.

My plan know is, when i have a little time, to run the motor for about 4 minutes, then pull full elevator in, whilst on the ground, that is in my garden.

Edited By Erfolg on 27/06/2013 10:17:49

[john farrell]

Posted by Tim Mackey on 23/06/2013 19:40:33:

For no apparant reason, other than my name being called out, I have "won" one of these models at the greenacres weekend fly-in. I have ordered some gear for it, but not sure when or if it will ever reach the top of my large "to do" list.

I am planning on using this motor, on either a 12 x 7 or perhaps 11 X 8 prop, and 4s Lipo.

I have this moto, though I have not installed it yet. Looking at the specs I think you will need to be looking at a 13 to 14 inch prop. I have purchased a 14 x 7 for mine (to ron on a 4s 4000 pack) but waiting for the Firenza to come back into stock - so no concrete figures as yet.

[Colin Carpenter]

Hi Erfolg. Hope you don`t mind me posting here but it`s the same model and seemed sensible. Just maidened the HK Rainbow F3A as the afternoon seemed ideal ! What a surprise ! Took off with bags of power vertically and needed just full down trim to level out . Stall was ok but I have kept it light as poss. Got 4 minutes out of a 3300 lipo and landed with no trouble which surprised me after reading up about the airframe. Using a Turnigy 3548 motor and servos and lipo and ESC. Changed one of the steel rods to piano wire as it was too tight in the outer and put on bigger wheels. Using a 11/5.5 prop at the mo as a 12/6 made motor too hot on tests and pulled too many amps for the motor.

That's the scary first flight out of the way. More testing to follow!

Colin

[Erfolg]

Colin

I do not know about the Rainbow version, the Firenza version has very poor stick on transfers.

I have only just started to fly it again and have found that even slow flying has the model tail low, as a consequence of trying to eck out the battery life. So I am now convinced that the model is not prone to tip stalling. The downside is that flight times are restricted.

I am at present using a 3500 lipo, probably a + 4000 battery would be better, to obtain a longer flight time. Although it would appear that at some point tip stalling becomes an issue as the weight increases.

[Colin Carpenter]

Hi Erfolg.

Yes It`s definitely the same model with a stainless steel spar and different but useless stickers which need tape to hold down . I use Sellotape Diamond clear. I have a similar lump of lead by the motor but think I need some more downthrust as it noses down under power off but thankfully seems to land similiarly to my Riot !

For £47 plus post it seems a bargain to me and will help teach me to perfect aerobatics which is my style of flying.I think the wing retaining system is quite novel and quick to assemble as it just about fits the Merc A class of SWMBO which is now our only car ,unassembled.

Got a weeks hols coming up so more testing afterwards.

Colin

[Colin Carpenter]

Hi. Thought I would add a couple of pics of the Rainbow. Had 20 mins flying now and our grass strip has managed to pull the tail wheel out of the pivot as well as doing the same to my Yak 54 ! Needs a good cut and roll.

Very pleased so far.

Colin

[Erfolg]

I have to say Colin that your model is far better finished than my own.

It looks that you have done the same as my self and fitted bigger wheels than come with the kit.

My own experience with the model that i need to use no less than 3/4 throttle, or the tail hangs low. At speed it flies well, being horizontal. There is an issue for me with duration, i get about 4 mins of flying, although I am using a 3200, 4s. rather than the by 2, 2200,4s.

With my model i could not get the two batteries in, other than in line, which would cause CG problems.

In my case the model was purchased as a "A" test work horse to back up my trainer. When it arrived I was somewhat taken aback by the size of the body and the long moment arm. For the "A" test it had one problem, that is the horizontal figure of 8. The small circles were not well suited to the model, particularly now that the cross over has to be tangential intersecting circles, rather than the previously permitted race track. However the two loop requirement of our club, was easy for the model, tracking true and making smooth large diameter loops.

My model has not shown any tendency to tip stall as reported on another USA model site, I assume because i have lighter batteries than some have used.

Edited By Erfolg on 23/03/2014 20:28:52

[Colin Carpenter]

Hi Erfolg. So far I find it will fly aerobatics at 55%-60% throttle and once set I can leave it alone at that setting and just fly. I can`t say it flies tail down but can eke out four and half minutes out of a 3300 4S lipo. I also agree about the tip stall but on only 5 flights am still cautious on landing.

Tail wheel repaired and hoping for Tuesday being flyable down here in Somerset .

My Riot will be used for an A test soon I hope.

Don`t look too close as the Tamiya red acrylic comes off when you look at it !!!

Colin