Real Tomahawk has more power



  • Hi, i enjoy my PA28, but i also just bought the PA38 Tomahawk, i regret my purchase ! This Tomahawk has no power to climb, it stalls too easy ! I got my PPL training on a real Tomahawk, so i have irl experience, this is not how a real Tomahawk flies ! Its engine is not as powerfull as the PA28 but the Just Flight PA38 behaves not at all as the real ...



  • And I worked directly with a PA38 pilot to create the flight dynamics, with a lot of head-scratching and fine tuning! He is very happy with it, obviously you are not. All I can suggest is that, over many years of use, each aircraft will have a history that builds into the characteristics (engine wear, airframe movement, control rigging etc) and they are going to be very individual aircraft in many respects.

    I can say is that this aircraft does behave as the real one our pilot flies, so there's not a lot more I can do. If you want to tweak it a little, I would suggest opening the aircraft.cfg file in notepad and, for the two areas you specifically mention, adjust the following lines:

    [propeller]
    thrust_scalar = 1.0 - make small changes, gradually build the thrust from the propeller but do not adjust the engine files above as that will affect the instrument readings.

    A little further down, under [flight_tuning] adjust in combination

    pitch_stability = 1.00
    roll_stability = 1.00
    yaw_stability = 1.00

    They will affect the overall stability of the aircraft (so general flight as well as stall behaviour) but the stall itself is built in to multiple tables in the airfile. See if you can find a balance where you are happy with it.

    Paul.



  • @pluto7777 I can confirm that I also see a lack of power for this aircraft. I've logged a ticket about the issue but am still waiting for a response two weeks later...



  • @preynolds @pluto7777 I've just taken the Tomahawk up for three brief climb tests, using flaps up / 70kts / 1670lb AUW as per figure 5-13 of the POH (climb performance).

    Altering the OAT to 0, 10 and 20 degrees at all heights from ground to 10,000ft, flying from Bidford Gliding Centre (135ft above MSL).

    0 degrees, I'm seeing a touch over 700fpm initially dropping to about 650fpm by 2000ft.

    10 degrees gives me 700fpm dropping to a little over 600 fpm by 2000ft

    20 degrees gives around 620fpm and drops to just under 600 fpm by 2000ft.

    That's pretty close to what the manual gives and is certainly within tolerance for a club aircraft. Unless you can show me something concrete which contradicts the POH, I'm not going to alter that. I have made a suggestion further up-thread about how you could increase the power for yourselves if you are unsatisfied with this.

    Cheers,
    Paul.



  • @Delta558 Hi Paul, thanks for your response. My ticket relates to cruise speed not climb performance. The documents provided give examples which simply cannot be achieved, being sometimes 19kts slower than published. That's a fairly substantial difference for this type of aircraft.
    I would also prefer not to have to start tweaking and testing/re-testing a product that I've paid good money for a developer to deliver. Apologies if this sounds a bit harsh but this isn't a throwaway £5 add-on.
    Please could I ask that you test various cruise speeds at 65/75% throttle as shown in the documentation and outlined in my ticket.
    Many thanks.
    Phil


  • JF Staff

    I would also prefer not to have to start tweaking and testing/re-testing a product that I've paid good money for a developer to deliver. Apologies if this sounds a bit harsh but this isn't a throwaway £5 add-on.

    I agree - that was, however, a suggestion if you wanted to bodge the supplied flight model that we think is accurate and has been well tested (and reviewed).
    We will definitely take a look at the numbers you have sent, but the PA-38 has been out for a while now and we review all feedback that we get after release.



  • @Derek thanks for the response. I appreciate the time and effort that goes into these add-ons and certainly don't want to be bodging anything. Great to hear you'll look at the cruise figures and look forward to a response in due course.
    Regards
    Phil



  • @Derek has anything been looked at with regard to this? I've also had no response at all on my support ticket #35291 for over 32 days now.


  • JF Staff

    @preynolds said in Real Tomahawk has more power:

    @Derek has anything been looked at with regard to this? I've also had no response at all on my support ticket #35291 for over 32 days now.

    I think that's because there isn't much to say but I will check the official response. I suspect you've had no reply as it's 'in the forum' - which is why we don't do support on the forums. Sorry about that.



  • @Derek no problem, I've had some response on the ticket so will continue with support there, thanks.


  • JF Staff

    I've contacted you both directly as we'd like to hear your feedback on the changes that we've been making to the FDE.



  • Now that v1.05 of the Tomahawk is out, it is my belief that things have gone overboard.

    I think @Delta558 was right, and I think your real-world Tommy pilot was right also. Version 1.02's FDE seemed to fly closer to the published numbers than v1.05.



  • @Mace_RB

    You are correct. I didn't get a chance to try the previous version so cannot comment on that. I purchased the PA38 only last night and just had an hour or so to look at it. My first impressions were that the aircraft was way over powered.

    The speed builds up nice and slow but once you hit 40knots the acceleration is ...well way to much. Rotating I got an initially climb of 1500 to 2000 feet per min. In every PA38 I've flown you are lucky to achieve 750 feet/min climb at 70kts, full power. With two people on board, full tanks 500 feet per minute is actually quite good. Once you get up to around 5000 feet this will drop to 250/300 feet per min, then you just get to the point where trying to climb further is useless particularity if you are going for a run that is less than 100nm.

    Cruise speed also seems to be a little on the high side. Even with full power set on the real aircraft in level flight you will only hit maybe 110knots before the engine RPM hits the red line. This feels a bit like hitting an invisible wall. In reality once you set the power back to 22-2300rpm and lean, the speed will usually drop back to 90knots. That is why all planning in the PA38 is done for 90 knots. Conversely despite being more power in the PA28-181 you will be lucky to get 100 knots. Even a fuel injected C172 will only yield a cruise speed of around 110. Just because the red line / VNE is 138knots doesn't mean you'll get anywhere near that unless you are in a dive.

    Power and performance between a PA28 and a PA38 there is no contest. The PA28 is way more powered, think 181 hp vs 112hp. God knows what the actual HP output is on real life club aircraft with 6000 hours on them. I once flew a PA38 that was from Germany and had a silencer fitted to the exhaust. This cost around 3 - 5 HP, it does not sound like a lot but boy could you feel the difference.

    If you chop the power on the PA38, it also glides only slightly more gracefully than a brick. In that sense you get alot more flexibility with your approaches, i.e. if you bugger it up you can ease back the power and it drops like a stone, unlike the PA28 which is much more slippy.

    Again the PA38 isn't a fast aircraft, it isn't meant to go anywhere in a hurry. It is a primary trainer where gaining time is more important, as most flights are training flights where you take off and land at the same airfield. It is better to have a slow and docile trainer for cross country too, that way the student does not have to think so fast. You'd be amazed at the mental effort required with a faster aircraft that has no autopilot (i.e. 30 knots difference on the cruise is massive when in congested airspace). There is a reason why a lot of pilots won't go near a PA38 if they had the choice.

    I have about 200 hrs in the real aircraft, and I wish the real one performed like this. Or maybe I am just too fat 🙂 Even if you avoid the bathroom scales the performance is so sensitive on the PA38 you notice if you are starting to pile on a few extra pounds, so the vertical speed indicator tells you so 🙂 I remember one winter afternoon, it was -10c, and we had a really high pressure system I think it was around 1040hPa - with fuel tanks half full, 1 POB and the PA38 was a mean machine!

    I shall have to spend more time with this aircraft in order to make further more detailed reports the above was just based on my first impression.

    I've also noticed that on the ground with the engine off, once you power up the fuel pump you get pressure - this is normal. However once you turn the pump off, the pressure goes away. in the real aircraft the pressure remains.



  • @EasyFlyer if you'd like you can send me your e-mail address since I don't know how to PM on this forum, may give you some further perspective on this. Or if you're on AVSIM (I think you are, if you're the same easyflyer) I am username Mace, if that is you, send me a pm there.

    I was playing around with v1.02 last night and I did get the approx climb figures you report. I tested service ceiling and with two adults and 50% fuel on board I got up to 11,000 MSL. Since the service ceiling is reportedly 13,000 feet, maybe a bit of a tweak with power (or critical altitude) in the flight model is in order with v1.02? But I do think maybe the 1.05 flight model is a bit much, as 1,200 fpm on initial climb rate seems high. However, I have zero hours in the real airplane so I will defer to those who do. I know it is not easy to tweak a flight model and I'm sure JustFlight have worked hard on it.



  • Hi

    I have to agree v1.02 behaved far more realistically than v1.05. This new version is far too over-powered, I'm climbing out of Liverpool at 2,000 fpm whereas in the real world I'd be lucky to achieve 700.

    Unfortunately I did not keep a copy of v1.02 and as I am currently learning to fly in a PA38 in the real world (G-VMCG & G-SUKI), I have stopped using the P3D version as its too unrealistic for me to practice my circuits.

    However I have to say the Xplane version is spot on!

    It's frustrating that the two versions are so far apart in terms of realism.