correct as-is T/O Trim at take off it doesn't act like it does in reality

[shon]

In reality, on the external F18 fuselage is configurated the load settings so that the system can automatically trims the aircraft by simply pressing the T/O Trim buttom before taking off. 

The above does not correspond to what was programmed by ED in his F18, taking away a lot of realism in such a delicate maneuver as a takeoff is, with an asymmetric load, having to manually press the lateral trim without being able to calculate in real detail how much increase you are applying to it because the numbers that appear in the FCS do not accurately reflect the trim presses made, but rather the system adjusts automatically for keeping the aircraft balanced when precisely it is not for carrying asymmetrical load.

Does ED plan to correct this, so that FCS recognizes the asymmetric load at takeoff and therefore the T/O Trim Reset takes into account automatically, as it happens in reality, all the parameters for a correct take off?? Thanks.

[Tholozor]

What is your source? Nothing in the NATOPS specifies that asymmetric loading is automatically accounted for by the T/O Trim button. The button only moves the stabilators to 12° nose up and neutralizes the MECH stick position (both with WonW, MECH stick only while in-flight). Asymmetric trim for a catapult shot is given as differential degrees of trim between the stabilators based on the asymmetric foot-pounds (Figure 8-1 in the NATOPS), and must be trimmed manually.

[shon]

Hi Tholozor, thanks for replaying.

My source is a real active Hornet pilot in the Spanish Air Force who I asked about this question. I am sure that if ED has contacted with real pilots as announced, they will know about this topic.

It is possible that the version of the Spanish F18 that I have received information about, specifically Hornets based in Gando in the Canary Islands that are about to be retired, are a different version from the one developed by ED.

In any case, let's be specific and precise: as you indicated, we have some tables in Natops to calculate the asymmetric trim. Perfect. So please, can someone tell us how we must get into the plane those values obtained? Does it really have to be done with several presses on the trim without you having any reference value to follow, unlike what happens when you trim the nose that you can manually go from 12° to the value you need in a precise way? So many tables and so many values so that later on the plane you don't have the precision to enter that data??

Edited August 13, 2022 by shon

[Swift.]

Spanish hornets are very different to any other hornet, unrecognisable almost.

And the asym trim us done exactly as Tholozor said, you use the chart which is asym loading in ft.lbs against difference in degrees between the stabs. It's exactly the same technique for measuring trim that you use for stuff like carrier trim settings.

So you calculate let's say 2 degrees difference:

1. Go to FCS

2. TO trim > Both stabs show 12

3. Trim into the lighter wing until the stabs show 11 and 13 (a 2 degree difference)

And you don't need to keep pressing the trim, just hold it down.

[shon]

Thank you Swift. I tried what you indicate at the time, but I was surprised that it is very difficult to obtain variation in lateral degrees, a lot, with a wide margin of time pressing the trim, very different from when you trim the nose compensator from 12° to 18°, much faster than the other.

That's why I was surprised and asked a real pilot how they did it. It is true that the Spanish F18 have had many updates. I don't know if one of them was this. But it is also true what you say that the Natops does not indicate anything other than what you indicate to trim laterally.

However, it would be great if in this aspect it were like the Spanish F18, since it would avoid you doing manual calculations that I don't think it happens in real life, but I suppose real pilots will have a software or at least a simple Excel that calculates it from automatic way...

[Tholozor]

I would imagine naval aviators are taught how to calculate it in order to obtain their asymmetric load for the landing limits. The NATOPS gives the lateral distance of the inboard and outboard stations from the centerline in order to do so.

Edited August 13, 2022 by Tholozor

[oldcrusty]

Without roll/yaw auto trim, which is the case here, we basically need the tables for launch only to keep the wings level (more or less) at flyoff airspeed. As we accelerate, corrections are needed until settled at cruise a/s. Any a/s change would require trim change. Same in PA mode. Trim until wings stop rolling at 'on speed'... for the most part. Then again, approaching and coming down the groove, it's constant wiggling left or right... I probably wouldn't even notice a minor pull one way or the other 

[Swift.]

It's also worth noting that these corrections are only prescribed for catapult launches. Shore based take offs can just be flown out.

Also also worth noting the amount of correction required for roll is only ever 1 or 2 degrees difference. So it's not a lot of work to trim it

[Steel Jaw]

 

On 8/14/2022 at 8:04 AM, Swift. said:

It's also worth noting that these corrections are only prescribed for catapult launches.

Comparing the Hornets from non carrier-owning nations like Spain Canada and Australia is a waste of time, different animals than the US naval version we fly.

Edited August 20, 2022 by BIGNEWY
removed 1.2 qoute

[Swift.]

10 minutes ago, Steel Jaw said:

Comparing the Hornets from non carrier-owning nations like Spain Canada and Australia is a waste of time, different animals than the US naval version we fly.

Yeah, but I dont see how that relates to what I said

[Grodin]

On 8/13/2022 at 8:55 PM, shon said:

Thank you Swift. I tried what you indicate at the time, but I was surprised that it is very difficult to obtain variation in lateral degrees, a lot, with a wide margin of time pressing the trim, very different from when you trim the nose compensator from 12° to 18°, much faster than the other.

That's why I was surprised and asked a real pilot how they did it. It is true that the Spanish F18 have had many updates. I don't know if one of them was this. But it is also true what you say that the Natops does not indicate anything other than what you indicate to trim laterally.

However, it would be great if in this aspect it were like the Spanish F18, since it would avoid you doing manual calculations that I don't think it happens in real life, but I suppose real pilots will have a software or at least a simple Excel that calculates it from automatic way...

 

While it would be awesome to have different versions of the hornet, some of them differ in so many ways (Spanish and Finnish hornets come to mind) compared to the currently modeled one that i don't think its happening. ED has been very specific about the module the make. Its not only a specific block hornet as operated by specific air force but also exactly specific year of that hornet, so bringing features from a very different model hornet doesn't seem likely.

[BIGNEWY]

I have cleaned the thread up, please remember the rules when posting

thanks